Continuous web of optical film laminate with predefined slit lines, and method and system for manufacturing the same

ABSTRACT

An optical film laminate that has predefined slit lines for enhancing both product accuracy and manufacturing speed in liquid-crystal display element manufacturing to radically improve manufacturing yield. The optical film laminate formed as a continuous web with the predefined slit lines for use in a continuous manufacturing system by laminating optically functional film sheets to liquid-crystal panels. The optical film laminate having defect-free regions having a predefined length corresponding to the dimension of a liquid-crystal panel and defective regions having a predefined length different from the defect-free region, based on the detected position of defects. The optical film laminate having a carrier film releasably laminated to an adhesive layer, wherein defect-free normal polarizing sheets and a defective polarizing sheets are formed on the carrier film by forming slit lines corresponding to above regions along the transverse direction of the optical film laminate.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional Application of U.S. patentapplication Ser. No. 12/849,341, filed Aug. 3, 2010, which is aContinuation Application of PCT application number PCT/JP2009/001689filed Apr. 13, 2009, which claims priority from PCT application numberPCT/JP2008/000987, filed on Apr. 15, 2008, the disclosure of which ishereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to a continuous web of an optical filmlaminate with predefined slit lines, and a method and system formanufacturing the same, the film laminate web being adapted for use in asystem for sequentially manufacturing LCD (Liquid-Crystal Display).

BACKGROUND

For a liquid-crystal display element to function, the direction oforientation of liquid-crystal molecules and the direction ofpolarization of the polarizer must be set in a particular relation toeach other. In liquid-crystal display element technologies, LCDs using aTN (Twisted Nematic) type liquid-crystal were the first to be put intopractical use. Recently, LCDs using a VA (vertical Alignment) typeliquid-crystal, an IPS (Inplane Switching) type liquid-crystal etc.,were put into practical use. Although a technical explanation isomitted, in an LCD using such TN-type liquid-crystal panel,liquid-crystal molecules are provided between two upper and lowerorientation films having respective rubbing directions on the innersurfaces of the substrates of the liquid-crystal panel. This means thatthe liquid-crystal molecules are twisted by 90 degrees along the opticalaxis, so that when a voltage is applied, the liquid-crystal moleculesare aligned in a direction perpendicular to the orientation films.However, in the case where the LCD is designed to allow images as seenfrom right and left sides of a display screen as those view fromdirectly in front of the display screen, the direction of rubbing on theorientation film at the viewing-side must be 45 degrees (the rubbingdirection of the other orientation film being 135 degrees). It istherefore necessary that the polarizing sheets made from the polarizingcomposite films to be laminated respectively on the front and back sidesof the liquid-crystal panel with polarizers respectively oriented indirections inclined respectively by 45 degrees with respect to alengthwise or widthwise direction of the display screen so as to conformto the rubbing directions.

Therefore, in a polarizing sheet for use in producing a liquid-crystaldisplay element of a TN-type liquid-crystal panel, it is required thatthe optical film is punched or cut into a rectangular-shaped sheethaving a long side or a short side determined in accordance with thesize of the TN liquid-crystal panel, and inclined by 45 degrees withrespect to the orientation direction of the polarizer produced bystretching in the lengthwise or widthwise direction. This is describedin Japanese Laid-Open Patent Publication No. JP 2003-161935A or JapanesePatent No. 3616866 B. The width or the short side dimension of theoptical film sheet to be processed into the rectangular shape is smallerthan the width of the optical film.

The punching or cutting of the optical film into the rectangular-shapedsheet may be collectively referred to as “individualized sheets” or “amethod and system for manufacturing individualized sheets” forliquid-crystal display elements. The optical film sheet thus punched orcut is produced by integrally punching or cutting not only thesurface-protection film but also the carrier film protecting the exposedsurface of the adhesive layer in the polarizing composite film. Theintegrally punched-out or cut carrier film sheet may be referred to as“separator,” rather than “carrier film sheet” because it is not servingas a transport medium. Thus, the manufacturing process of theliquid-crystal display elements includes the first step of peeling theseparator from each of the optical film sheet to have the adhesive layerin the polarizing sheet exposed. Subsequently, the polarizing sheetseach having the adhesive layer exposed are conveyed one-by-one, forexample, under a vacuum suction irrespective of whether thesurface-protection films are laminated on the polarizing sheets or not,and laminated to respective ones of a plurality of liquid-crystalpanels. According to the aforementioned manufacturing process of theliquid-crystal display elements, it has been required that theintegrally punched-out or cut sheet from the optical film is in the formof an individualized sheet having four trimmed sides and a certain levelof stiffness of less deflection or bend and which can be conveyed andlaminated easily. During the initial period in the history of themanufacturing process of the liquid-crystal display elements, theoptical film sheet or a polarizing sheet comprised in such optical filmsheet was generally known as a “polarizing plate” which is still used asa common name.

In the manufacturing process of TN-type liquid-crystal display elements,an optical film fed out from a roll of continuous web is integrally andsequentially punched-out or cut in a direction transverse to the feeddirection. However, in this case, it is impossible to obtain a finishedliquid-crystal display element simply by sequentially laminating thesheets formed to respective ones of a plurality of liquid-crystalpanels. This is because the sheets each formed with a long or short sideextending in a direction 45 degrees cannot be laminated sequentially torespective ones of the liquid-crystal panels with the same posture.Therefore, to provide a finished liquid-crystal display element bytransporting a polarizing sheet to a position for lamination with aliquid-crystal panel, and then laminating the polarizing sheet to theliquid-crystal panel, an optical film in the form of a continuous webhaving a width greater than a long side of a liquid-crystal panel is fedout in a lengthwise direction, and each of the sheets are punched-out atan angled direction of 45 degrees with respect to the lengthwisedirection, using, for example, a die into a plurality of individualpolarizing sheet, and appropriately fed to the lamination process withthe liquid-crystal panel, as shown in the Japanese Laid-Open PatentPublication No. 2003-161935A or Japanese Patent No. 3616866B.Alternatively, manufacturing methods for liquid-crystal display elementsare provided wherein one of the methods uses a single sheet formed fromthe continuous web of the optical film, the single sheet having asubstantially large width by punching or cutting the optical film in adirection 45 degrees inclined with respect to the lengthwise directionas shown in the Japanese Patent Publication No. 62-14810B or JapaneseLaid-Open Patent Publication No. 55-120005A. The liquid-crystal displayelement is produced by making the elongated optical film having a widthof the liquid-crystal panel thus formed into a continuous roll, feedingthe elongated optical film from the continuous roll, forming a pluralityof sheets having required length by cutting the film in the widthwisedirection with respect to its feed direction and laminating theplurality of the polarizing sheets contained in the sheet to respectiveone of liquid-crystal panels W sequentially conveyed. At any rate, theabove techniques are not beyond the system for manufacturingindividualized sheets based on the premise of TN-type liquid-crystaldisplay elements.

Japanese Patent Publication No. 62-14810B discloses, prior to theVA-type liquid-crystal and the IPS-type liquid-crystal being broughtinto practical use, an apparatus to produce a liquid-crystal panel.Japanese Patent Publication No. 62-14810B further discloses a techniqueof continuously feeding out an optical film which comprises a polarizingcomposite film (in Japanese Patent Publication No. 62-14810B, referredto as “elongated polarizing plate”) and a separator for protecting anadhesive layer on the polarizing composite film, “cutting only thepolarizing plate 4 and the adhesive layer 5 while leaving the separator6 uncut (hereinafter referred to as “half-cut”),” removing defectivepolarizing sheets formed in the course of the feeding, sequentiallylaminating the peeled sheets onto a plurality of liquid-crystal panels(referred to as “liquid-crystal cells”) for constituting small-sizedisplay screens of electronic calculators or the like, while peeling theseparator from the polarizing sheets which have been retained on theseparator. The apparatus is a labeler unit which produces an LCD usingthe TN-type liquid-crystal. Thus, the optical film to be used, ofcourse, must be an elongated sheet produced from an optical film havingsubstantially large width by cutting it in a direction 45 degreesoblique to the longitudinal direction of the optical film with a widthcorresponding to the width of the liquid-crystal panel. Therefore, thisapparatus cannot be applied directly to a manufacturing apparatusadapted to perform steps of continuously forming a plurality ofpolarizing sheets from an optical film and laminating respective sheetsto respective ones of the liquid-crystal panel using VA-type or IPS-typeliquid-crystal to produce liquid-crystal display elements because of thewidth of optical film required.

Japanese Laid-Open Patent Publication No. 55-120005A discloses, prior tothe VA-type liquid-crystal and the IPS-type liquid-crystal being broughtinto practical use, an apparatus to produce a liquid-crystal displayelement by sequentially laminating a plurality of sheets formed into arequired length to a plurality of liquid-crystal panels whilecontinuously feeding out an optical film containing a polarizingcomposite film. In the manufacturing method disclosed an adhesive layeris formed on a large-width polarizing composite film. A plurality ofelongated polarizing composite film sheets having a required width arecut out from the large-width polarizing composite film. These sheets arelaminated to separately prepared conveyance medium (i.e., carrier film)subjected to a releasing treatment to produce an optical film. Then, theoptical film is half-cut in a vertical direction by two knives providedwith a required distance with respect to a longitudinal direction,leaving the conveyance medium uncut, the optical film sheet iscontinuously formed separated from each other on the conveyance medium,and the plurality of formed sheets are sequentially laminated torespective ones of the liquid-crystal panels being conveyed tomanufacture the liquid-crystal element. This apparatus is also based onthe use of an elongated polarizing sheet which is cut in a direction 45degrees oblique to the stretching direction of the polarizing compositefilm with a width corresponding to the width of the liquid-crystalpanel, so that it cannot be applied directly to a manufacturingapparatus adapted to VA-type or IPS-type liquid-crystal to produceliquid-crystal display elements.

Automation of manufacturing process for liquid-crystal display elementsusing individualized sheets is described, for example, in JapaneseLaid-Open Patent Publication No. 2002-23151A. Flexible individualizedsheets tend to be bowed or warped due to curves or distortion of itsedge, and thus it is a serious technical impediment to accuracy andspeed in registration and lamination with liquid-crystal panels. Thus,it will be understood that the individualized sheet is required to havea certain level of thickness and stiffness to facilitate registrationand lamination with liquid-crystal panels typically in transportationunder suction. For example, the disclosures in the Japanese Laid-OpenPatent Publication No. 2004-144913A, Japanese Laid-Open PatentPublication No. 2005-298208A or Japanese Laid-Open Patent PublicationNo. 2006-58411A disclose measures for addressing such technicalproblems.

On the other hand, the VA-type and IPS-type liquid-crystal panels arenot designed to arrange liquid-crystal molecules in twistedorientations. Thus, when producing liquid-crystal display element usingthese types of liquid-crystal panels, there is no need to have thepolarization axis of the polarizing sheet oriented at 45 degrees. Eachof these liquid-crystal display elements using these liquid-crystalpanels is formed by applying sheets to the opposite sides of theliquid-crystal display panel oriented with their polarization axescrossed at 90 degrees. In the case of the VA-type and IPS-typeliquid-crystal panels, with respect to the viewing anglecharacteristics, maximum contrast can be obtained along the direction ofthe polarizing axis of the polarizing sheet, so that the sheets havepolarizing axes oriented in parallel with the longitudinal or transversedirection of the liquid-crystal panel from the technical view point ofsymmetry of the viewing angle characteristics and visibility. Thus,these sheets to be applied to the liquid-crystal panel has a featurethat the optical film including a polarizing composite film which hasbeen subjected to a longitudinal or transverse stretching can becontinuously fed out from a roll and cut along transverse lines withrespect to the feed direction of the optical film to sequentiallyproduce rectangular polarizing sheets including the polarizing sheetshaving the same width as the optical film width.

Because of the improved viewing angle characteristics, VA-typeliquid-crystal or the IPS-type liquid-crystal are more widely adoptedthan the TN type. In view of such trend in environments of technicaldevelopments, proposals have been made such as the one described inJapanese Laid-Open Patent Publication No. 2004-361741A which is based onuse of the VA-type or IPS-type liquid-crystal panels and comprises stepsof continuously feeding an optical film laminate comprising a polarizingcomposite film, cutting the optical film laminate in conformity to thesize of a liquid-crystal panel and sequentially laminating a pluralityof sheets which have been produced by the cutting step to respectiveones of a plurality of the liquid-crystal panels.

However, the mainstream of manufacture of liquid-crystal displayelements is still based on the manufacturing technology utilizingindividualized sheets, due to the following technical problems. Inmanufacturing liquid-crystal display elements, a critical technicalchallenge is to detect any defect which may otherwise be retained in thedisplay elements to be formed, and to prevent any defective product frombeing produced. This makes it possible to significantly improvemanufacturing yield. Most of the product defects primarily arise fromdefects in the polarizing composite film contained in the optical film.However, it is not practical to provide an optical film after completelyremoving all defects contained in individual films which are to belaminated together to form the optical film. The reason is that,observation for defects in the polarizing composite film on all of thepolarizer and the protection film laminated on the polarizer to providea polarizing composite film having no adhesive layer formed thereon, andan adhesive layer formed on the polarizing composite film indicates thatthere are various kinds of defects, including defects inherent in thePVA film of the polarizer itself, defects arose in connection with thelamination of the protection film to the polarizer and defects generatedin the adhesive layer of the formed polarizing composite film,distributed in 20 to 200 positions over a unit length of the polarizingcomposite film of 1000 m. Thus, it is extremely difficult to produce adefect-free optical film under existing circumstances. To maintainquality of display elements, it is not permitted to use a polarizingcomposite film sheet having visible flaws or defects for a sheet fortelevision display element even if such a flaw or defect is small.Therefore, if lengths of the polarizing composite film with defects areused to form a display and a display requires 1 m of film, 20 to 200defective liquid-crystal display elements out of 1,000 products will beproduced.

A proposed preliminary inspection apparatus for a polarizing compositefilm, is disclosed, for example, in Japanese Patent No. 3974400B andJapanese Laid-Open Patent Publications Nos. 2005-62165A and 2007-64989A.

Japanese Laid-Open Patent Publication 2007-140046A discloses a methodthat comprises peeling a carrier film from an optical film fed outcontinuously from a continuous roll to expose a polarizing compositefilm having an adhesive layer, detecting a defect or defects present inthe polarizing composite film, punching or cutting only normal regionsof a polarizing composite film into a rectangular shape, while leavingthe defective region or regions of the polarizing composite filmuntouched. Japanese Patent Application No. 2007-266200 is a disclosurerelating to a method and a system for laminating a polarizing sheet to aliquid-crystal panel. However, the method and system disclosed cause notonly substantial complexity in the entire system for laminating but alsoan increase in the number of steps and difficulty in control for eachstep, and therefore, cause corresponding reduction in the manufacturingspeed.

The present disclosure has been made based on the above relateddisclosures and through intensive researches and considerations forsignificantly enhancing product accuracy and manufacturing speed, anddrastically improving manufacturing yield, in the manufacture ofliquid-crystal display elements.

SUMMARY

The present disclosure is based on findings that solutions of theaforementioned technical problems can be achieved by forming slit lines,in a transverse direction of an optical film laminate, at positionscorresponding to regions defined in accordance with position orpositions of one or more defects existing in and detected through apreliminary inspection of a continuous web of the optical film laminate,the optical film laminate being adapted for use in a system forsequentially manufacturing liquid-crystal display elements by laminatingoptically functional film sheets to respective ones of liquid-crystalpanels, wherein the optically functional film is formed to have apredefined dimension corresponding to a dimension of a liquid-crystalpanel having a predefined size to form a sheet, and wherein the slitlines define sheets which are determined as normal polarizing sheetsadapted to be laminated to respective ones of the liquid-crystal panels,the normal sheets being on the carrier film which is included in theoptical film laminate, and wherein the present disclosure has thefollowing features based on the aforementioned findings.

The disclosure provides a continuous web of an optical film laminate,and a method and apparatus for producing the continuous web of anoptical. The continuous web of optical film laminate optical filmlaminate being adapted for use in a system for sequentiallymanufacturing liquid-crystal display elements by laminating opticallyfunctional film sheets to respective ones of liquid-crystal panels, saidoptically functional film being formed to have a predefined dimensioncorresponding to a dimension of a liquid-crystal panel having apredefined size. The optical film laminate comprising of (1) anoptically functional film; the optically functional film including, atleast one defect-free region with no defects; and at least one defectiveregion having at least one defect, the at least one defect-free regionand the at least one defective region defined by predefined slit lines,(2) an adhesive layer provided on optically functional film, and (3) acarrier film releasably laminated on said adhesive layer. Thedefect-free and defective regions being defined along the longitudinaldirection in accordance with position of a defect existing in theoptically functional film and are detected through a preliminaryinspection. The defect-free region having a predefined lengthcorresponding to the dimension of the liquid-crystal panel. Thedefective region being defined as a region having a predefined lengthwhich is different from the length of said defect-free region. Thelength of the defective region being defined to include the position ofthe defect. The slit lines being formed in a transverse direction ofsaid optical film laminate at a side opposite to said carrier film to adepth reaching a surface of said carrier film adjacent to said adhesivelayer.

The method for producing the continuous web of an optical film laminateincluding the steps of (a) laminating a continuous web of a protectionfilm on at least one of opposite surfaces of a continuous web of apolarizer film to form an optically functional film, having alongitudinal direction, (b) inspecting surfaces and inside of theoptically functional film to detect a position of a defect existing inthe optically functional film (c) releasably laminating a continuous webof a carrier film on the continuous web of the optically functional filmby an adhesive layer to form a continuous web of the optical filmlaminate, wherein the optically functional film includes at least onedefect-free region and at least one defective region, the at least onedefect-free and at least one defective region being defined along thelongitudinal direction of the optically functional film in accordancewith the position of the detected defect, said defect-free region havinga predefined length corresponding to said dimension of theliquid-crystal panels, said defective region including at least onedefect and defined as a region having a predefined length which isdifferent from the length of said defect-free region, the length of thedefective region being defined across said position of the defect, and(d) sequentially forming slit lines in a transverse direction of saidoptical film laminate at a side opposite to said carrier film to a depthreaching a surface of said carrier film adjacent to said adhesive layerto form, on the carrier film, at least one defect-free, normal opticallyfunctional film sheet having no defect and at least one defectiveoptically functional film sheet having at least one defect, andseparated from the normal sheet, to thereby form a continuous web of theoptical film laminate with slit lines including optically functionalfilm sheets.

The apparatus for producing a continuous web of an optical film laminatecomprising (a) a provisional optical film laminate feeding unit forfeeding a provisional optical film laminate at least including acontinuous web of an optically functional film and a continuous web of aprovisional carrier film, the continuous web of the optically functionalfilm including a laminated web having a polarizer in the form of acontinuous web and a protection film laminated on at least one ofopposite surfaces of the continuous web of the polarizer, and anadhesive layer provided on one of opposite surfaces of the laminatedweb, the continuous web of the provisional carrier film being releasablylaminating on the adhesive layer, (b) a provisional carrier film peelingunit for peeling the provisional carrier film from the provisionaloptical film laminate to expose the adhesive layer of the opticallyfunctional film, (c) an inspection unit for inspecting surfaces andinside of the optically functional film with the adhesive layer in theexposed state to detect position of a defect existing in the opticallyfunctional film, (d) an optical film laminate forming unit of adapted toreleasably laminate a continuous web of a carrier film on the continuousweb of the optically functional film through an adhesive layer to form acontinuous web of the optical film laminate, wherein the opticallyfunctional film comprising at least one defect-free region having nodefect and at least one defective region, the defect-free region and thedefective region being defined along longitudinal direction inaccordance with the position of the detected defect, said defect-freeregion having a predefined length corresponding to said dimension of theliquid-crystal panels, said defective region including at least defectand defined as a region having a predefined length which is differentfrom that the length of the defect-free region, the length of thedefective region being defined across the position of the defect, (e) aslitting unit for sequentially forming slit lines in a transversedirection of said optical film laminate at a side opposite to saidcarrier film adjacent to said adhesive layer, said slit lines forming atleast one defect-free normal sheet and at least one defective sheethaving at least one defect and being separated from the normal sheet onsaid carrier film, to thereby form a continuous web of the optical filmlaminate having slit lines formed therein and including opticallyfunctional film sheets, and (f) a control unit adapted to controlrespective operations of at least the provisional optical film laminatefeeding unit, the provisional carrier film peeling unit, the inspectionunit, the optical film laminate forming unit, and the slitting unit, inan inter-related manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example, and not bylimitation, in the figures of the accompanying drawings in whichelements having the same reference numeral designations represent likeelements throughout and wherein:

FIG. 1A is a view showing typical example of a liquid-crystal displayelement for a widescreen television having a diagonal screen size of 42inches. FIG. 1B is an enlarged view of a corner of the liquid-crystaldisplay shown in FIG. 1A.

FIG. 2 is a schematic diagram showing a system for continuouslymanufacturing liquid-crystal display elements wherein defect-free sheetsof an optically functional film are formed and laminated onliquid-crystal panels through inspection of defects in the opticallyfunctional film, without interrupting the feed of the continuous web ofthe optically functional film being fed.

FIGS. 3A, 3B and 3C are schematic diagrams showing the structure of anoptical film laminate with predefined slit lines for use in continuousmanufacturing of a liquid-crystal display element according to at leastone embodiment.

FIG. 4 is a schematic diagram showing a continuous manufacturing systemfor liquid-crystal display elements according to one embodiment, whereinthe system comprises a feed apparatus for feeding a continuous web of anoptical film laminate with predefined slit lines, and aliquid-crystal-panel conveyance apparatus for feeding a plurality ofliquid-crystal panels to be laminated with a polarizing sheet having anadhesive layer constituting the continuous web of optical film laminatewith predefined slit lines.

FIG. 5 is a flowchart showing manufacturing processes or process stepsin the continuous manufacturing system for liquid-crystal displayelements in FIG. 4.

FIG. 6 is a schematic diagram showing the relationship between a controlunit for controlling device of the feed apparatus of the continuous webof the optical-film laminate with predefined slit lines and theliquid-crystal-panel conveyance apparatus illustrated in FIG. 4, andinformation read and imaged by a determination unit in the continuousmanufacturing system of the liquid-crystal display element according toat least one embodiment.

FIGS. 7A and 7B are a schematic diagrams showing adefective-polarizing-sheet removal unit comprising (1) a dummy-filmdrive mechanism including a movable roller disposed in a feed passagefor a continuous web of optical film laminate with predefined slit linesor (2) a dummy-film drive mechanism including a movable roller adaptedto be replaced with one of the lamination rollers from a pair of thelamination rollers disposed at lamination station B, according to atleast one embodiment.

FIG. 8 is a schematic diagram showing the state when a pre-alignmentunit, a final-alignment unit, a conveyance unit for conveying the panelsto the lamination position and a panel-edge detection unit in theliquid-crystal-panel conveyance apparatus are controlled, based on theinformation on the sheets determined by the determination unit, to allowa liquid-crystal panel to be conveyed in a controlled posture, in theliquid-crystal display element continuous manufacturing system accordingto at least one embodiment.

FIG. 9 is a schematic diagram showing a lamination unit withliquid-crystal panels comprising a sheet-edge detection unit fordetecting a leading edge of a normal polarizing sheet of a polarizingcomposite film constituting the continuous web of optical film laminatewith predefined slit lines.

FIG. 10 is a schematic diagram showing a manufacturing method and systemfor a continuous web of an optical film laminate with predefined slitlines, according to at least one embodiment.

FIG. 11 is a schematic diagram showing a manufacturing method and systemfor a continuous web of an optical film laminate with predefined slitlines, according to at least one embodiment.

FIG. 12 is a flowchart showing manufacturing processes or process stepsin the manufacturing method and system for a continuous web of anoptical film laminate with predefined slit lines according to at leastone embodiment.

FIG. 13 is a flowchart showing manufacturing processes or process stepsin the manufacturing method and system for a continuous web of anoptical film laminate with predefined slit lines according to at leastone embodiment.

FIG. 14 is a schematic diagram showing the operation of a slittingposition checkup unit, together with the inspection method for checkinga difference between the position of the slit line actually formed in adirection transverse to a feeding direction and a position at which theslit line is to be formed (position of the reference slit line) on thecontinuous web of the optical film laminate, the slit line is calculatedbased on the feed-length measurement data of the fed-out length of theoptical film laminate according to at least one embodiment.

FIG. 15 is a schematic diagram showing a technique of calculating aposition for forming a slit line in a continuous web of an optical filmlaminate to segment a region of a polarizing composite film into adefective region and a defect-free region according to at least oneembodiment.

FIG. 16 is a flowchart showing a step to form slit line in a techniqueof storing defect identification information x_(γ) according to at leastone embodiment.

FIG. 17 is a flowchart showing a step to form a slit line in a techniqueof modifying a distance to a next-slit-line formation position to(x′+x₀′) wherein x₀′>x₀, according to at least one embodiment.

FIG. 18 is a flowchart showing a step to form slit line in a techniqueof modifying a distance to a next-slit-line formation position to[(x′+x₀)/m] wherein m=2 or more, according to at least one embodiment.

FIG. 19 is a schematic diagram showing a manufacturing system for acontinuous web of an optical film laminate with predefined slit lineshaving three inspection units, according to at least one embodiment.

FIG. 20 is a table showing a defect inspection unit, types of defect anda defect detection method according to at least one embodiment.

EXPLANATION OF NUMERICAL CHARACTERS

The following numerical characters are used throughout the descriptionto refer to the following features

1: continuous manufacturing system for liquid-crystal element 5:polarizing sheet 6: optically functional film sheet 10: optical filmlaminate with predefined slit lines 11: polarizing composite film 11″:polarizing composite film without adhesive layer 12: adhesive layer 13:carrier film 13′: provisional carrier film 14: surface-protection film15: optical film laminate 15′: provisional optical film laminate 16:slit line 100: feed apparatus 110: support rack 120: film feed unitincluding a feed roller 130: reading unit 140: speed adjustment unitincluding a dancer roller 150: defective-polarizing-sheet removal unit160: film feed unit including a feed roller 170: straight-ahead-posturedetection unit 180: carrier film take-up drive mechanism 190: panel-edgedetection unit 200: lamination unit 300: liquid-crystal panel conveyanceunit 400: control unit 410: information processing device 420: storagedevice 500: manufacturing system for continuous web of optical filmlaminate with predefined slit lines according to an embodiment 500′:manufacturing system for continuous web of optical film laminate withpredefined slit lines according to the embodiment shown in FIG. 11 510:polarizer manufacturing line 510′: roll of provisional optical filmlaminate 520, 520′: protection film manufacturing line 525: support rack530: manufacturing line for polarizing composite film without adhesivelayer 11″ 530′: manufacturing line for polarizing composite film withadhesive layer 540: manufacturing line for continuous web of opticalfilm laminate 550: manufacturing line for continuous web of optical filmlaminate with predefined slit lines 560: lamination drive mechanism560′: film feed drive mechanism 561: pair of lamination rollers 561′:pair of feed rollers 570, 570′: distance measurement device 580:inspection unit 590: carrier film lamination unit 600: slitting unit610: slitting position checkup unit 620: roll of manufactured continuousweb of optical film laminate with predefined slit lines 630: take-updrive mechanism 640: lamination unit 650: provisional carrier filmtake-up drive mechanism 651: provisional-carrier-film peeling unit 700:control unit 710: information processing device 720: storage device 800:manufacturing system for continuous roll of optical film laminate 810:film feed unit 820: take-up drive mechanism 830: the first inspectionunit 840: the second inspection unit 850: the third inspection unit 860:carrier film feed unit 870: surface-protection film feed unit 900:control unit 910: information processing device 920: storage device

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the disclosed embodiments. It will be apparent,however, that the disclosed embodiments may be practiced without thesespecific details. In other instances, well-known structures and devicesare schematically shown in order to simplify the drawing.

Taking a widescreen television having a diagonal screen size of 42inches as an example, a liquid-crystal panel W therefore comprises alayered liquid-crystal panel which includes a pair of rectangular-shapedsubstrates each having a size of about 540 to 560 mm in length×about 950to 970 mm in width×about 0.7 mm (700 μm) in thickness, and aliquid-crystal layer having a thickness of about 5 μm having atransparent electrode, a color filter etc., and sandwiched between thesubstrates, by a as shown in FIG. 1. Therefore, the thickness of theliquid-crystal panel W itself is about 1.4 mm (1400 μm). Theliquid-crystal display element typically has a polarizing sheet 5,commonly referred to as “a polarizing plate,” adhesively applied to eachof a front side (viewing side) and a back side (backlight side) thereof.

Although the substrates are usually formed from glass, this disclosureis not limited to glass substrates. Other materials such as plastics orcomposites made from various glass and plastic materials may be used toform either one or both of the substrates.

The present disclosure will now be described with reference to specificembodiments illustrated in the accompanying drawings.

1. General Description of Continuous Web of Optical Film Laminate withPredefined Slit Lines

FIG. 3A shows a continuous web of an optical film laminate 15 and FIG.3B shows a continuous web of an optical film laminate with predefinedslit lines 10 according to one embodiment of the present disclosure, onwhich optically functional film sheets 6 of polarizing composite films11 are formed on a carrier film 13. The optically functional film sheets6 are separated by slit lines 16. The slit lines 16 are formedsequentially in a transverse direction of the continuous web of theoptical film laminate. Among the optically functional film sheets beingformed in cut-state on the carrier film 13, the optically functionalfilm sheets 6 to be laminated with the liquid-crystal panel W are, asdescribed later, formed by two slit lines 16, one on upstream side andone on downstream side of a defect-free position in an opticallyfunctional film that is defined based on defect positions in theoptically functional film. FIG. 3C is a schematic diagram showing aliquid-crystal display element manufactured by laminating polarizingsheets 5 that are formed by separating the above mentioned opticallyfunctional film sheets 6 from the carrier film 13, to a liquid-crystalpanel.

The continuous web of an optical film laminate with predefined slitlines 10 including an optically functional film sheet 6 to be laminatedto a liquid-crystal panel W, according to various embodiments, is anoptical film laminate with predefined slit lines 10 including acontinuous web of an optical film laminate 15 comprised of an polarizingcomposite film 11 including a polarizer having an adhesive layer 12provided on the surface of the polarizer which has a transparentprotection film laminated thereon and which is to be attached to aliquid-crystal panel W, a carrier film 13 releasably laminated to theadhesive layer 12 and a surface-protection film 14 releasably laminatedon the surface of the optically functional film opposite to the surfaceon which the carrier film 13 is laminated. The optical film laminatewith predefined slit lines 10 is formed separately where the polarizingcomposite film 11 and the surface-protection film 14 on the carrier film13 are cut integrally along slit lines formed sequentially in thetransverse direction of the continuous web of the optical film laminate15. Hereinafter, unless it is necessary to differentiate from others,the term “optical film with predefined slit lines” will be used toexpress the optical film laminate with predefined slit lines in variousembodiments.

The polarizing composite film 11 is a film, generally including acontinuous web of the polarizer, two protection films laminated onrespective ones of the opposite surfaces of the continuous web of thepolarizer, and an acrylic adhesive layer 12 formed on one side of thepolarizer which is to be applied to the liquid-crystal panel W. Thecarrier film 13 is a film that is releasably laminated to the adhesivelayer 12 to provide a function of protecting the exposed side of theexposed adhesive layer 12 of the polarizing composite film 11. Thepolarizing composite film 11 is formed through the following process,for example. First, a continuous web of a polarizer having a thicknessof 20 to 30 μm is formed by subjecting a PVA (polyvinyl alcohol)-basedfilm having a thickness of about 50 to 80 μm to a dyeing treatment usingiodine and a cross-linking treatment; and subjecting the resultantPVA-based film to an orientation treatment based on stretching in alengthwise or widthwise direction thereof. As a result, the iodinecomplex is oriented in the direction parallel to the stretchingdirection of the PVA-based film to acquire a property of absorbing apolarized light having a plane of oscillation matching with theorientation of the iodine complex to thereby provide a polarizer havingabsorption axes in the direction parallel to the stretching direction.Thus, in order to produce a continuous web of a polarizer having anexcellent optical property in addition to excellent uniformity andaccuracy, it is desirable that the stretching direction of the PVA-basedfilm corresponds to the lengthwise or widthwise directions of the film.Generally, the absorption axis of the polarizer or the opticallyfunctional film including such polarizer is parallel to the lengthwisedirection of the optically functional film, and the polarizing axis isin the widthwise direction perpendicular to the absorption axis. Then,the protection film is laminated to one or each of the opposite surfacesof the formed continuous web of the polarizer with an adhesive. Finally,on one side of the continuous web of the polarizer with the protectionfilm laminated, the acrylic adhesive layer 12 to be applied to theliquid-crystal panel W is formed. Generally, a transparent TAC(triacetylcellulose)-based film having a thickness of about 40 to 80 μmis often used as the protection film for protecting the continuous webof the polarizer. In the following description, the continuous web ofthe polarizer may be simply referred to as “polarizer.” In addition,unless it is necessary to differentiate, the optically functional filmmay be simply referred to as “polarizing composite film.”

According to the definition of terms in “SEMI (Semiconductor Equipmentand Materials International) Draft Document” on polarizing films forflat-panel display elements including liquid-crystal display elements(FPD Polarizing Films), the term corresponding to the “polarizingcomposite film and layer” constituting a polarizing composite film foruse in a liquid-crystal display element is referred to as “films andlayer composing polarizing films.” Thus, the polarizing composite film11 in the perspective view at FIG. 3A is interpreted as corresponding tothe “film composing polarizing films,” so-called a polarizing compositefilm. Thus, the sheet in the perspective view at FIG. 3C which is formedin a rectangular shape from the polarizing composite film 11,corresponds to “polarizing films,” so that it may apply the term“polarizing sheet” to the latter, rather than the commonly called name“polarizing plate.” In the following description, a film including apolarizer, a protection film laminated on one or both of oppositesurfaces of the polarizer, and an adhesive layer formed on one side ofthe polarizer to be laminated to a liquid-crystal panel W, will bereferred to as “polarizing composite film,” and a sheet commonly calledby the name “polarizing plate,” which is formed in a rectangular shapefrom the polarizing composite film, will be referred to as “polarizingsheet” or simply “sheet.” In addition, when a sheet is formed from anoptical film including a polarizing composite film having asurface-protection film and a carrier film attached thereto, and whenthis sheet has to be distinguished from “a polarizing sheet,” the formeris referred to as “an optical film sheet,” and a sheet formed from thesurface-protection film or the carrier film included in the compositefilm is respectively referred to as “a surface-protection film sheet” or“a carrier film sheet” respectively.

The thickness of the polarizing composite film 11 generally has athickness of about 110 to 220 μm. The polarizing composite film 11 isgenerally comprised of a polarizer having a thickness of about 20 to 30μm, a protection film which thickness may be about 80 to 160 μm when twoprotection films are laminated on respective ones of opposite surfacesof the polarizer, and an adhesive layer 12 which thickness formed on oneside of the polarizer to be laminated to a liquid-crystal panel W isabout 10 to 30 μm. The polarizing composite films 11 are laminated torespective ones of the front and back sides of the liquid-crystal panelW with the adhesive layer 12 in such a manner that polarizing axesintersect each other at an angle of 90 degrees. Thus, in manufacturing aliquid-crystal display element for a widescreen television having adiagonal screen size of 42 inch, on an assumption that a thickness of aliquid-crystal panel W itself is about 1400 μm, and since the thicknessof the polarizing composite film 11 is in the range of 110 to 220 μm,the liquid-crystal display element itself has an overall thickness ofabout 1620 to 1840 μm. The thickness of the liquid-crystal displayelement is still within 2.0 mm or less. In this case, the ratio of thethickness of the liquid-crystal display element to the overall thicknessof the liquid-crystal panel W, and the polarizing composite film 11 isabout 10:1.5 to 10:3. If use is made of a polarizing composite film 11having a protection film laminated to only one surface of the polarizer,and an adhesive layer 12 formed on the other surface of the polarizer,from the viewpoint of reducing the thickness of the liquid-crystaldisplay element, the thickness of the polarizing composite film 11itself can be reduced to 70 to 140 μm, so that an overall thickness ofthe resultant liquid-crystal display element is reduced to a range ofabout 1540 to 1680 μm. The ratio of the thickness of the liquid-crystalelement to that of the liquid-crystal panel W and the polarizingcomposite film 11 will be in the range of about 10:1 to 10:2.

A continuous web of an optical film with predefined slit lines 10,according to various embodiments, for use in a liquid-crystal displayelement has a structure as shown in FIG. 3B. The structure of theoptical film with predefined slit lines 10 will be briefly describedbelow, in connection with a manufacturing process thereof. Asurface-protection film 14 with an adhesive surface having a thicknessof about 60 to 70 μm is releasably laminated to the surface of apolarizing composite film 11 devoid of an adhesive layer, and a carrierfilm 13 is releasably laminated to an adhesive layer 12 provided on thesurface of a polarizing composite film 11 which is to be laminated tothe liquid-crystal panel W for providing a function of protecting theadhesive layer 12. Typically, a PET (polyethylene terephthalate)-basedfilm is used for each of the carrier film 13 and the surface-protectionfilm 14. During the manufacturing process of the liquid-crystal displayelement, the carrier film 13 generally serves as a carrying medium(carrier) for the polarizing composite film, as well as the means toprotect the adhesive layer 12, and thus it will hereinafter be referredto as a “carrier film.” Both of the carrier film 13 and thesurface-protection film 14 are so-called “manufacturing-processmaterials” which are to be peeled and removed prior to the final stageof the manufacturing process of the liquid-crystal display element toform polarizing sheet 5. Both of the films are to be used for protectingthe non-adhesive surface from being soiled or damaged, and alsoprotecting the exposed surface of the adhesive layer, of the polarizingcomposite film 11, during the manufacturing process of theliquid-crystal display elements.

In the polarizing composite film 11, one of the protection films forprotecting the polarizer may be replaced with a phase difference filmmade of a cycloolefin-based polymer, a TAC-based polymer or the like andhaving an optical compensation function. It may further be provided as alayer of a transparent substrate, such as a TAC-based substrate, havinga polymer material, such as a polyester-based polymer or apolyimide-based polymer applied/arranged thereto and then cured.Further, in the case of a polarizing composite film to be laminated tothe backlight side of the liquid-crystal display element, it may bepossible to provide an additional function by laminating a brightnessenhancement film to the backlight side protection film of the polarizer.In addition, regarding the structure of the polarizing composite film11, there have been proposed various other variations, such as atechnique of laminating a TAC-based film to one of opposite surfaces ofthe polarizer and laminating a PET film to the other surface of thepolarizer.

One of the methods for providing a polarizing composite film withoutadhesive layer 11″ including a polarizer and a protection film laminatedon one or both of opposite surfaces of the polarizer devoid of anadhesive layer 12 for attaching to a liquid-crystal panel W comprises astep of laminating a carrier film 13 having a transferable adhesivelayer formed thereon, to the surface of the polarizing composite filmwithout adhesive layer 11″ to be laminated to the liquid-crystal panelW. A specific transfer technique is as follows. In a manufacturingprocess of the carrier film 13, the carrier film is subjected to areleasing treatment at the surface which is to be laminated to thepolarizing composite film without adhesive layer 11″ at the surface ofthe polarizing composite film without adhesive layer 11″ which is to belaminated to the liquid-crystal panel W, and then a solvent containingadhesive is applied to the treated surface and dried to form an adhesivelayer on the carrier film 13. Then, the carrier film 13 having theformed adhesive layer is laminated to the polarizing composite filmwithout adhesive layer 11″, for example, while feeding out the carrierfilm 13 and feeding out the polarizing composite film without adhesivelayer 11″ in the same manner, so that the adhesive layer formed on thecarrier film 13 can be transferred to the polarizing composite filmwithout adhesive layer 11″, and the adhesive layer is formed.Alternatively, instead of the adhesive layer formed in this manner, theadhesive layer 12 may be formed by directly applying a solventcontaining adhesive to the surface of the polarizing composite filmwithout adhesive layer 11″ to be laminated to the liquid-crystal panel,and drying the same.

The surface-protection film 14 typically has an adhesive surface. Unlikethe adhesive layer 12 on the polarizing composite film 11, the adhesivesurface must be peeled from a polarizing sheet 6 of the polarizingcomposite film 11 together with a surface-protection film 14 (not shown)when the surface-protection film 14 is peeled and removed from theoptically functional film sheet 6 during the manufacturing process ofthe liquid-crystal display elements. The reason is that thesurface-protection film 14 which is formed together with the polarizingcomposite film 11 is adapted for protecting the surface of thepolarizing composite film 11 devoid of an adhesive layer 12 from therisk of being soiled or damaged, but not an adhesive surface to betransferred to the surface of the polarizing composite film 11. Theperspective view at FIG. 3C shows the state of the polarizing sheet 5after the surface-protection film 14 is peeled and removed. It shouldfurther be noted that, irrespective of whether the polarizing compositefilm 11 has a surface-protection film laminated thereon, it may bepossible to provide the polarizing composite film 11 at the surface ofthe protection film on the front side of the polarizing composite filmwith a hard coat treatment for protecting the outermost surface of theliquid-crystal display element, and/or a surface treatment for obtainingan anti-glare effect or the like, such as an anti-glare treatment.

As described above, in the manufacture of VA-type and IPS-typeliquid-crystal panels, there is no restriction requiring that the twopolarizing sheets are laminated to respective ones of front and rearsurfaces of the liquid-crystal panel with the polarization axis of eachof the polarizing sheets oriented at 45 degrees oblique with respect tothe major or minor side of the liquid-crystal display element, asexperienced in the manufacture of TN-type liquid-crystal panels, due tothe viewing angle characteristics inherent to the orientation of theliquid-crystal, because the polarization axes of the opticallyfunctional films or the polarizing sheets to be laminated to respectiveones of front and rear surfaces of the liquid-crystal panel are requiredto be oriented substantially exactly 0 degree or 90 degrees to thedirection of the sides of the liquid-crystal panels which are indifferent directions each other by 90 degrees. Therefore, in a processfor continuously manufacturing liquid-crystal display elements using theVA-type and IPS-type liquid-crystal panels, it becomes possible to carryout the process through steps of separating an optically functional filmsheet from a carrier film and continuously laminating the sheet torespective ones of a plurality of liquid-crystal panels, during the feedof the optical film laminate, wherein the optical film laminatecomprises a carrier film on which an optically functional film sheet isreleasably laminated. In addition, during the feed of the optical filmlaminate containing the carrier film on which the optically functionalfilm sheet is releasably laminated, if only the sheets determined to bethe defect-free, normal polarizing sheets are laminated to respectiveones of a plurality of liquid-crystal panels to make liquid-crystaldisplay elements, without interrupting the feed of the optical filmlaminate, it is possible to obtain enhanced product accuracy andmanufacturing speed as well as significantly improved production yieldin the manufacture of liquid-crystal display elements.

2. A Continuous Manufacturing System and Method for Liquid-CrystalDisplay Element

(General Description of a Continuous Manufacturing System forLiquid-Crystal Display Elements)

FIG. 4 is a schematic diagram showing a continuous manufacturing system1 for manufacturing liquid-crystal display elements. The systemcomprises a feed apparatus 100 for feeding a continuous web of anoptical film with predefined slit lines 10. It also comprises aliquid-crystal panel conveyance unit 300 for conveying each of aplurality of liquid-crystal panels W, wherein a continuous web of anoptical film with predefined slit lines 10 comprising normal polarizingsheets x_(α) and defective polarizing sheets x_(β) separated from thenormal polarizing sheet of the polarizing film 11 formed by cutting theweb along slit lines 16 which are sequentially formed in a transversedirection of the optical film, and a carrier film 13 releasablylaminated to an adhesive layer 12 of the polarizing composite film 11 isfed to a lamination station B, and each of the plurality ofliquid-crystal panels W to be sequentially laminated with only thenormal polarizing sheets x_(α) 5 which have the carrier film 13 removedare fed in synchronization with the feed of normal polarizing sheetsx_(α).

FIG. 5 is a flowchart showing a manufacturing process or process stepsin the continuous manufacturing system for the liquid-crystal displayelement shown in FIG. 4. FIG. 6 is a schematic diagram showing therelationship between a control unit 400 for controlling each of the feedapparatus 100 for the continuous web of the optical-film laminate withpredefined slit lines 10, the liquid-crystal-panel lamination unit 200for laminating only the normal polarizing sheet x_(α) to theliquid-crystal panel, the liquid-crystal panel conveyance unit 300, andinformation read and imaged by a reading unit 130 from the slit lines 16sequentially formed on the continuous web of the optical film withpredefined slit lines 10, in the continuous manufacturing system of theliquid-crystal display element according to various embodiments.

The feed apparatus 100 for feeding a continuous web of an optical-filmwith predefined slit lines 10 comprises a support rack 110 for rotatablymounting a continuous roll of a continuous web of an optical film withpredefined slit lines 10 according to one embodiment of the presentdisclosure, as shown in FIG. 4, a film feed unit including a feed roller120, a reading unit 130 for determining whether each of the polarizingcomposite film sheets 6 formed separately on the carrier film 13 bycutting the web along slit lines 16 sequentially formed in a widthwisedirection with respect to the feed direction of the continuous web ofthe optical film 10 being fed, is a normal polarizing sheet x_(α) or adefective polarizing sheet x_(β), in connection with the control unit400 at a determination station A, a speed adjustment unit including adancer roller 140 for providing a constant speed film feeding, adefective-polarizing-sheet removal unit 150 provided at a removalstation C, for peeling and removing a slit defective polarizing sheetx_(β) from the carrier film 13 by operating a movable roller 152 inconnection with the control unit 400, a film feed unit including a feedroller 160, a lamination unit 200 provided at a lamination station B,for peeling the normal polarizing sheets x_(α) from the carrier film 13which are formed separately from other sheets by cutting the web alongslit lines 16 sequentially formed in a widthwise direction on thecarrier film, and laminating each of the normal polarizing sheets x_(α)to respective ones of the liquid-crystal panels W by operating a pair oflamination rollers at least adapted to be moved toward and away fromeach other in connection with the control unit 400, a carrier-filmtake-up drive mechanism 180 for taking up the carrier film 13, apanel-edge detection unit 190 for detecting a leading edge of the normalpolarizing sheet x_(α) provided at the lamination station B and anstraight-ahead-posture detection unit 170 for measuring deviations ofthe normal polarizing sheet xα in the feed direction and the transversedirection formed on the carrier film 13, for example, by taking imagesof the sheet using the CCD camera and subjecting the taken images to animage processing, whereby the measured deviations are calculated interms of x, y and θ.

(Composition of the Continuous Web of Optical Film with Predefined SlitLines)

The continuous web of the optical film with predefined slit lines 10according to various embodiments provided in the feed apparatus 100 hasa width corresponding to a length of a long or short side of aliquid-crystal panel to which it is applied. As shown in FIG. 3A, a filmhaving a transparent protection film laminated on one or each of theopposite surfaces of the polarizer is used for the polarizing compositefilm 11 that comprises the continuous web of the optical film laminate15 before forming slit lines. As shown in FIG. 3B, the continuous web ofthe optical film with predefined slit lines 10 comprises a continuousweb of the optical film with predefined slit lines comprising acontinuous web of an optical film laminate 15 comprised of a polarizingcomposite film 11 including a polarizer having an adhesive layer 12provided on the surface of the polarizer which has a transparentprotection film laminated thereon and which is to be attached to aliquid-crystal panel W, and a carrier film 13 releasably laminated onthe adhesive layer 12, and optically functional film sheet 6 are formedseparately on the carrier film 13 by cutting the web along slit lines 16which are sequentially formed in a transverse direction of the opticalfilm laminate 15. FIG. 3C is a schematic diagram showing aliquid-crystal display element in which two polarizing sheets 5 peeledfrom the carrier film 13 are applied to the opposite sides theliquid-crystal panel W with their polarization axes crossed at 90degrees crossing angle. As shown in FIG. 3A and FIG. 3B, a continuousweb of an optical film laminate 15 wherein a surface-protection film 14having an adhesive layer is additionally releasably laminated on thesurface of the polarizing composite film opposite to the surface onwhich the carrier film 13 is laminated, can be used to make a continuousweb of an optical film with predefined slit lines wherein the polarizingcomposite film 11 and the surface-protection film 14 sheet on thecarrier film 13 are cut integrally, if necessary.

The carrier film 13 primarily is a releasable film adapted to protectthe adhesive layer 12 of the polarizing composite film 11 during themanufacturing of a continuous web of an optical film with predefinedslit lines and of liquid-crystal display elements. Therefore, thecarrier film is peeled, taken up, and removed from the adhesive layer 12prior to or during lamination to the liquid-crystal panel W. The carrierfilm 13, although it is a releasable film, in various embodiments, is acarrying medium (that is, a carrier film) to carry polarizing sheets 6which are formed separately on the carrier film 13 by cutting the webalong slit lines 16 sequentially formed in a transverse direction on thecarrier film, to the lamination station B. Thus, the term “carrier film”is used in various embodiments instead of using “releasable film.”

The continuous web of optical film with predefined slit lines 10 ismanufactured by two methods as follows, and details of manufacturingmethods for the continuous web of optical film with predefined slitlines 10 will be described later. Each of the manufacturing methods isoutlined as follows. First, a continuous web of a polarizing compositefilm without adhesive layer 11″ is manufactured with asurface-protection film laminated to at least one of the surfaces of thepolarizer and is immediately transported to an inspection station M. Atthe inspection station M, defects in the polarizing composite filmwithout adhesive layer 11″ are detected by inspecting the surface andthe inside of the transported continuous web of the polarizing compositefilm without adhesive layer 11″. Then, based on the detected positionsof defects, information processing is carried out on the continuous webof the polarizing composite film without adhesive layer 11″. Thus, onthe continuous web of the polarizing composite film 11, a defect-freeregion (x_(α)) having a predefined length corresponding to the dimensionof the liquid-crystal panel W in the longitudinal direction and adefective region (x_(β)) including at least one defect and defined as aregion having a predefined length which is different from the length ofthe defect-free region and being defined across the position of thedefect, are defined along the widthwise direction with respect to thelongitudinal direction of the web.

The slitting unit installed at a slit-forming station N is operatedbased on the processed information of the defective position to formslits in the transverse direction, each corresponding to the regionsdefined along the widthwise direction with respect to the longitudinaldirection, and sequentially form slit lines on the continuous web ofoptical film laminate 15 manufactured after the information processing.After information processing at the inspection station M, the carrierfilm 13 is releasably laminated by the adhesive layer 12 to thecontinuous web of the polarizing composite film without adhesive layer11″, to manufacture the continuous web of the optical film laminate 15.When necessary, it is possible to manufacture a continuous web of anoptical film laminate 15 in which a surface-protection film 14 having anadhesive layer is releasably laminated on the polarizing composite filmopposite to the surface on which the carrier film 13 is laminated.

The manufactured continuous web of optical film laminate 15 is thencarried to the slit-forming station N. The slitting unit provided at theslit-forming station N forms slit lines 16 that correspond to each ofthe region defined in the widthwise direction with respect to thelongitudinal direction, or the defect-free region (x_(α)) and thedefective region (x_(β)) on the carried optical film laminate 15, theslit lines are formed sequentially in the transverse direction on theoptical film laminate 15 at the side opposite to the carrier film to adepth reaching a surface of the carrier film 13 adjacent to the adhesivelayer. Thus, between the two slit lines 16 formed in sequence on thecarrier film 13, one on the upstream side and one on the downstream sideof the feeding direction, the defect-free sheet and the defectivepolarizing sheet, or the normal polarizing sheet and the defectivepolarizing sheet of the polarizing composite film without adhesive layer11″ comprising the surface-protection film 14 are formed separated fromeach other when necessary. The continuous web of the optical film withpredefined slit lines 10 is obtained finally in this manner. This is thefirst manufacturing method of the continuous web of the optical filmwith predefined slit lines 10.

The second manufacturing method of the continuous web of the opticalfilm with predefined slit lines 10 is one that uses a continuous web ofa provisional optical film laminate 15 that comprises a polarizingcomposite film 11 having at least an adhesive layer 12 preliminarilyprovided, and a provisional carrier film 13′ that is releasablylaminated to the adhesive layer 12. First, the continuous web of theprovisional optical film laminate 15′ is provided, for example, in theform of a continuous roll and is provided to the manufacturing process.Then, the continuous web of the provisional optical film laminate 15′ isfed out from the continuous roll and provided to a peeling station L. Atthe peeling station L, the provisional carrier film 13′ that comprisesthe fed continuous web of the provisional optical film laminate 15′ ispeeled from the adhesive layer 12 of the polarizing composite film 11,and thus the polarizing composite film 11 having the adhesive layer 12is exposed.

The polarizing composite film 11 having the exposed adhesive layer 12 istransported in the form of the continuous web to the inspection stationM. At the inspection station M, defects in the continuous web of thepolarizing composite film 11 having the adhesive layer are detected byinspecting the surface and the inside of the transported polarizingcomposite film 11 having the adhesive layer 12. Then, based on thedetected positions of defects, information processing is carried out onthe continuous web of the polarizing composite film 11 having theadhesive layer 12. Thus, on the continuous web of the polarizingcomposite film 11 having the adhesive layer 12, a defect-free region(x_(α)) having a predefined length corresponding to the dimension of theliquid-crystal panel W in the longitudinal direction and a defectiveregion (x_(β)) including at least one defect and defined as a regionhaving a predefined length which is different from the length of thedefect-free region and being defined across the position of the defect,are defined along the widthwise direction with respect to thelongitudinal direction of the web. In the first manufacturing method,the defect inspection is carried out on the polarizing composite filmwithout adhesive layer 11″ before the adhesive layer 12 is formed, butin the second manufacturing method, the defect inspection is carried outon the polarizing composite film 11 having the adhesive layer 12.

The slitting unit installed at the slit-forming station N is operatedbased on the processed information of the defective position to formslits in the transverse direction each corresponding to the regionsdefined along the widthwise direction with respect to the longitudinaldirection, and sequentially form slit lines 16 on the continuous web ofoptical film laminate 15 manufactured after the information processing.After information processing at the inspection station M, the carrierfilm 13 replaces the peeled provisional carrier film 13′ to bereleasably laminated to the adhesive layer 12 to manufacture acontinuous web of an optical film laminate 15. When necessary, it ispossible to manufacture a continuous web of an optical film laminate 15in which a surface-protection film 14 is releasably laminated on thepolarizing composite film opposite to the surface on which the carrierfilm 13 is laminated.

From hereafter, in both manufacturing methods, the manufactured opticalfilm laminate 15 is fed to the slit-forming station N to finallycomplete the continuous web of the optical film with predefined slitlines 10. Thus, between the two slit lines 16 formed in sequence on thecarrier film 13, one on the upstream side and one on the downstream sideof the feeding direction, the defect-free sheets and the defectivepolarizing sheets of the polarizing composite film 11 comprising thesurface-protection film 14, or the normal polarizing sheets x_(α) andthe defective polarizing sheets x_(β) are formed separately in thecompleted continuous web of the optical film with predefined slit lines,when necessary. A process to manufacture a continuous web of an opticalfilm with predefined slit lines 10 into a continuous roll can beincluded in both methods, when necessary.

(General Description of Liquid-Crystal Display Element Manufacturing)

The manufacturing method for liquid-crystal display elements using acontinuous web of an optical film with predefined slit lines 10 isoutlined as following referring to FIGS. 4 and 5. As shown in FIG. 4, acontinuous web of an optical film with predefined slit lines 10 isloaded to a support rack 110 in a form, for example, of a continuousroll. As shown by the step 1 in FIG. 5, the optical film with predefinedslit lines 10 fed out from the continuous roll is transported to thedetermination station A where a reading unit 130 having a CCD inconnection with the control unit 400 is provided, as shown in FIG. 6.

At the determination station A, the reading unit 130 determines, inconnection with the control unit 400, whether the optically functionalfilm sheet 6 being separated on the carrier film 13 formed by cuttingthe web along the slit lines 16 which are formed in a widthwisedirection with respect to the feed direction of the optical film withpredefined slit lines 10 are the normal polarizing sheet x_(α) or thedefective polarizing sheet x_(β). The reading unit 130, for example,takes images of the sequentially formed slit lines on the optical filmwith predefined slit lines 10 and produce picturized images by anoptical sensor including a CCD camera. Then, for example, a measurementdevice including an encoder measures a length in the longitudinaldirection of a sheet (x) between the two slit lines, one on upstreamside and one on downstream side. As shown by step 2 in FIG. 5, forexample, it is possible to determine whether a measured sheet is anormal polarizing sheet x_(α) or a defective polarizing sheet x_(β) asfollows.

Specifically, the information processing is sequentially carried out onthe measured length in the longitudinal direction of a sheet (x) in aninformation processing device 410 and a storage device 420 provided inthe control unit 400 as follows:

(1) the first slit line 16 on the continuous web of the optical filmwith predefined slit lines 10 that is fed out from the continuous rollis determined in terms of differences in contrasts in the image taken bythe reading unit 130;

(2) simultaneously, the encoder provided in the feed roller of the filmfeed unit including a feed roller 120 measures a feed-out distance ofthe continuous web of the optical film with predefined slit lines 10;

(3) the next slit line is determined as in the above (1) and the fedlength between the two slit lines 16, i.e., a length of a sheet (x) iscalculated and stored;

(4) then, when, for example, a length of a sheet (x) is determined to bedifferent from the predefined length (x_(α)) of a preliminarily storednormal polarizing sheet x_(α), i.e., when the length of a sheet (x) isdetermined to be shorter or longer than the predefined length (x_(α)) ofa preliminarily stored normal polarizing sheet x_(α), then the sheet isdetermined to be a defective polarizing sheet x_(β). When the length ofa sheet (x) is determined to be equal to the predefined length (x_(α))of a preliminarily stored normal polarizing sheet x_(α), i.e., when bothhave equal length, the sheet is determined to be a normal polarizingsheet x_(α); and

(5) the control unit 400 stores each of the determined positions ofnormal polarizing sheets x_(α) and defective polarizing sheets x_(β) inthe storage device 420 in terms of, for example, a feed-out distancefrom the reference point recorded on the continuous web of the opticalfilm 10 with predefined slit lines.

When a defective sheet x_(β) on the carrier film 13 is transported tothe removal station C, as shown by steps 3 to 6 in FIG. 5, the controlunit 400 sends an instruction to remove the defective polarizing sheetx_(β) based on the stored position information of the defectivepolarizing sheet x_(β) and operates the defective-polarizing-sheetremoval unit 150 including a movable roller, by controlling theoperations of the speed adjustment unit including a dancer roller 140for providing a constant speed film feeding and the feed unit includinga feed roller 160 in an inter-related manner. Thedefective-polarizing-sheet removal unit 150, as shown by step 7 in FIG.5, peels and removes only the sheets determined to be the defectivepolarizing sheets x_(β) from the carrier film 13 among the opticallyfunctional film sheets 6 being formed separately in sequence on thecarrier film 13.

As shown by steps 8 to 10 in FIG. 5, at the removal station C, thecontinuous web of the optical film with predefined slit lines 10 withthe defective polarizing sheet x_(β) removed from the carrier film 13includes only the normal polarizing sheets x_(α) in cut-state betweenthe two slit lines 16 on the carrier film 13 one on upstream side andone on downstream side on the carrier film 13, and is transported to thelamination station B by the film feed unit including the feed roller 160and a carrier-film take up drive mechanism 180 for taking up the carrierfilm in connection with the control unit 400. At that moment, thestraight-ahead-posture detection unit 170 checks whether the feedingdirection and widthwise direction of the normal polarizing sheets x_(α)being formed on the carrier film 13 matches with the reference line.

As shown in FIG. 9, only the carrier film 13 is peeled by being bent atan acute angle, via the peeling plate 211, by the carrier-film take-updrive mechanism 180. By having the carrier film 13 peeled by being bentat an acute angle, the adhesive layer of the normal polarizing sheetsx_(α) may be gradually exposed. The leading edge of the normalpolarizing sheet x_(α), as being gradually peeled from the carrier film13, is detected by the panel-edge detection unit 190. Preferably, thenormal polarizing sheets x_(α), while being gradually peeled, istransported to the lamination unit 200 at the lamination station B afterthe feeding speed the sheets is adjusted to the speed of the laminationwith the liquid-crystal panel W. This makes it possible to slightlyexpose the leading edge of the normal polarizing sheet x_(α) to allowthe leading edge of the liquid-crystal panel W sequentially conveyed tothis edge position to be aligned with the leading edge of the normalpolarizing sheet x_(α). The details of the liquid-crystal panelconveyance unit 300, shown by steps 11 to 16 in FIG. 5, will bedescribed later.

(Operation of the System for Manufacturing Liquid-Crystal DisplayElements)

In operation of the entire continuous manufacturing system 1 forliquid-crystal panels, a continuous web of a roll of a dummy film isfirst mounted on the continuous manufacturing system 1. The continuousweb of the dummy film is unrolled from the continuous roll under tensionby means of the control unit 400 including first and second film feedunits including feed rollers 120, 160 each including feed rollers andthe speed adjustment unit including a dancer roller 140. The continuousweb of the dummy film is advanced until its leading edge reaches aposition where, under a normal operation, the carrier film 13 is peeledfrom the normal polarizing sheet x_(α), the carrier film 13 from whichthe normal polarizing sheet is peeled is passed through the peelingplate 201 and taken up by the carrier-film take up drive mechanism 180.Then, the trailing end of the continuous web of the dummy film isconnected to the leading end of the continuous web of the optical filmwith predefined slit lines 10, and a supply of the continuous web of theoptical film with predefined slit lines is initiated.

(Removal of Defective Polarizing Sheet x_(β))

The operation of the defective-polarizing-sheet removal unit 150 inconnection with the control unit 400 in the manufacturing process of theliquid-crystal panels is described below. The defective-polarizing-sheetremoval unit 150 is operated under the control of the control unit 400.FIGS. 7A and 7B show such defective-sheet removal unit 150 that peelsand removes defective polarizing sheets x_(β) from the carrier film 13,which are sheets determined as defective polarizing sheets β by thereading unit 130 among normal polarizing sheets x_(α) and defectivepolarizing sheets x_(β) being formed separately on the carrier film 13included in the continuous web of optical film with predefined slitlines 10. The defective-polarizing-sheet removal unit 150 comprises bothof the dummy film drive mechanism 151 and the movable roller 152.

The defective-polarizing-sheet removal unit 150 in FIG. 7A comprises adummy-film drive mechanism 151 having a function of attaching to thereonand peeling the defective polarizing sheet x_(β) releasably laminated tothe carrier film 13 and a movable roller 152 adapted to be activatedbased on the removal instruction from the control unit 400 when thedefective polarizing sheet x_(β) reaches a position in a feed path ofthe continuous web of the optical film with slit lines 10 where removalof the defective polarizing sheet is to be initiated, and thus the feedpath of the continuous web of the optical film with slit lines 10 ismoved so that the feed path contacts the dummy-film feed path of thedummy-film drive mechanism 151. Then, the defective polarizing sheetx_(β) on the carrier film 13 is peeled from the carrier film 13 as beingattached to the feed path of the dummy film feed path and removed fromthe feed path of the continuous web of the optical film with predefinedslit lines 10. After the defective polarizing sheet x_(β) is removed,the movable roller 152 returns to the original position, and the feedpath of the continuous web of the optical film with predefined slitlines 10 and that of the dummy film driven by the dummy film drivemechanism 151 are detached.

The defective-polarizing-sheet removal unit 150 illustrated in FIG. 7Bis configured, under control of the control unit 400, to be moved in aninter-related manner with the lamination unit 200 including the pair oflamination rollers provided at the lamination station B. It comprises adummy-film drive mechanism 151 having a function of releasably attachingand peeling the defective polarizing sheet x_(β), and a movable roller152 defining a dummy-film feed path of the dummy-film drive mechanism151. The removal unit illustrated in FIG. 7B is different from theremoval unit illustrated in FIG. 7 (1) in that, in the removal unitillustrated in FIG. 7B, the movable roller 152 defining the dummy-filmfeed path disposed adjacent to the pair of lamination rollers of thelamination unit 200 at the lamination station B is arranged in areplaceable manner with one of the lamination rollers of the pair oflamination rollers in the lamination unit 200.

More specifically, when the defective polarizing sheet x_(β) reaches anend position (i.e., the removal initiation position) of the feed path ofthe continuous web of the optical film with predefined slit lines, thepair of lamination rollers are moved apart from each other, and themovable roller 152 defining the dummy film feed path is moved to a nipbetween the lamination rollers in spaced-apart relation to replace theroller with one of the rollers of the pair of lamination rollers. Thus,the movable roller 152 and the other laminating roller are operated inan inter-related manner. In this instance, the carrier film 13 is takenup by the carrier-film take up drive mechanism 180, and the defectivepolarizing sheet x_(β) is peeled from the carrier film 13 and the peeleddefective polarizing sheet x_(β) is attached to the dummy-film feed pathby means of the movable roller 152 operated in an inter-related mannerwith the other roller of the pair lamination rollers and removed withoutbeing laminated to the liquid-crystal panel W. After the defectivepolarizing sheet x_(β) is removed, the movable roller 152 returns to theoriginal position, and the laminating roller that was replaced by themovable roller returns to the position to be operated in aninter-related manner with the other laminating roller, i.e., theinter-related operation of the defective-polarizing-sheet removal unit150 and the lamination unit 200 is released. Then, when a normalpolarizing sheet x_(α) on the carrier film 13 reaches to the laminationposition, the lamination unit 200 is adapted to make the replacedlamination roller to be operated in an inter-related manner with theother lamination roller, so that the normal polarizing sheet x_(α) isattached to the liquid-crystal panel.

(Conveyance of Liquid-Crystal Panel W)

A brief description of the liquid-crystal panel conveyance unit 300 forconveying the liquid-crystal panel W to the lamination unit 200,including a pair of laminating rollers adapted to be vertically movedtoward and away form each other for laminating the liquid-crystal panelW with the normal polarizing sheet x_(α) and formed separated on thecarrier film 13 of the continuous web of the optical film withpredefined slit lines 10, will be given below.

Taking a large size television having a diagonal screen dimension of 42inches as an example, a rectangular-shaped liquid-crystal panel W has asize of about 540 to 560 mm in length and about 950 to 970 mm in widthas shown in FIG. 1. During the manufacture process of liquid-crystaldisplay elements, the liquid-crystal panel W is slightly trimmed alongits peripheries during a wiring stage including mounting operations ofelectronic components. Alternatively, the liquid-crystal panel W may betransported or conveyed with peripheries already trimmed. Theliquid-crystal panels W are taken out one-by-one from a magazinecontaining a large number of liquid-crystal panels, by means of aliquid-crystal-panel supply apparatus, and as shown by steps 11 to 16 inFIG. 5, conveyed through cleaning/polishing stage to the lamination unit200 at the lamination station B for lamination with respective ones ofthe normal polarizing sheet x_(α), by the liquid-crystal panelconveyance unit 300, by being adjusted to equal intervals and a constanttransportation speed. The normal polarizing sheet x_(α) is formed fromthe continuous web of the optical film with predefined slit lines tohave a size slightly less than that of the liquid-crystal panel W.

FIG. 8 is a schematic diagram showing, the conveyance of theliquid-crystal panel W in an aligned orientation, by means of thecontrol unit 400 controlling the pre-alignment unit 310, thefinal-alignment unit 320, the conveyance unit 330 for conveying thepanels to the lamination position and the panel-edge detection unit 340which are provided in the liquid-crystal panel conveyance unit 300,based on the information on the sheet determined by the reading unit 130as a normal polarizing sheet x_(α) during the manufacturing process ofliquid-crystal display elements. The liquid-crystal panel conveyanceunit 300 includes a liquid-crystal panel orientation controlling unitcomprising a pre-alignment unit 310, a final-alignment unit 320, aconveyance unit for conveying the panels to the lamination position 330,and a panel-edge-detection unit 340 for detecting the leading edge ofthe liquid-crystal panel W, for aligning the orientation of theliquid-crystal panel W in a final stage of the conveyance of theliquid-crystal panel W sequentially supplied to the lamination station Bwhen the normal polarizing sheet x_(α) is transported to the laminationstation B, in synchronization with the transportation of the normalpolarizing sheet x_(α).

(Lamination of Normal Sheet x_(α) to Liquid-Crystal Panel W)

As shown in FIG. 9, the leading edge of the normal polarizing sheetx_(α) is moved to the nip defined between the pair of lamination rollersof the lamination unit 200 which are now in the vertically spaced apartrelation to each other, and detected by the panel-edge detection unit190. Although the normal polarizing sheet x_(α) is fed in a statelaminated on the carrier film 13, it is seldom that the normalpolarizing sheet x_(α) is accurately fed so that the angle θ between thefeed direction and the lengthwise direction of the carrier film 13becomes zero. Therefore, deviations of the normal polarizing sheet x_(α)in the feed direction and the transverse direction are measured, forexample, by taking images of the sheet using the CCD camera of thestraight-ahead-posture detection unit 170 and subjecting the takenimages to an image processing, whereby the measured deviations arecalculated in terms of x, y and θ, and the calculated data is stored inthe storage device 420 by the control unit 400.

The liquid-crystal panels W are sequentially positioned by thepre-alignment unit 310, so that they are aligned in lengthwise andwidthwise directions respectively with the transport direction and thedirection transverse to the transport direction in the conveyance path.The positioned liquid-crystal panel W is conveyed to and placed on thefinal-alignment unit 320 which includes an alignment table adapted to beturned by a drive mechanism which is controlled by the control unit 400.The leading edge of the liquid-crystal panel W placed on the alignmenttable is detected by the panel-edge detection unit 340. The position ofthe detected leading edge of the liquid-crystal panel W is checked formatch with the reference lamination position stored in the storagedevice, specifically, the calculation data in terms of x, y and θ torepresent the orientation of the normal polarizing sheet x_(α) to belaminated to the liquid-crystal panel W. For example, the deviationbetween the leading edge of the liquid-crystal panel W and the referencelamination position is measured using an alignment mark of theliquid-crystal panel W illustrated in FIG. 1 to calculate the angulardisplacement θ, and the alignment table having the liquid-crystal panelW placed thereon is turned by the angular displacement θ. Then, thealignment table is connected to the conveyance unit 330 directed for thelamination unit 200 at the lamination station B. The liquid-crystalpanel W is conveyed to the lamination position while keeping the sameorientation, by the conveyance unit 330 directed for the lamination unit200 at the lamination station B. The leading edge of the liquid-crystalpanel W is registered with and laid on the leading edge of the normalpolarizing sheet x_(α) at the lamination unit 200, as shown in FIG. 8.In the final stage, the normal polarizing sheet x_(α) and theliquid-crystal panel W which are in aligned relation with each other andare held between the pair of lamination rollers and conveyed thereby toobtain a finished liquid-crystal display element.

The normal polarizing sheet x_(α) is fed to the lamination position forlamination with the liquid-crystal panel W together with the carrierfilm 13 within the continuous web of the optical film with predefineslit lines 10 advanced under tension. The normal polarizing sheet x_(α)can be gradually peeled from the carrier film 13, so that there is leastpossibility that the periphery of the normal polarizing sheet x_(α) isbent or sagged as shown in FIG. 9. This makes it easy to have theorientation of the liquid-crystal panel W aligned with the normalpolarizing sheet x_(α). Such method and system increases themanufacturing speed of the liquid-crystal display element and improvesthe product accuracy which has not been unachievable in themanufacturing process utilizing the individualized sheets, the processutilizing the individualized sheets to complete a liquid-crystal displayelement includes steps of; after peeling a separator from each of theindividualized sheets to expose the adhesive layer and feeding under avacuum suction each of the sheets to a lamination position, adjustingthe position of the sheet with respect to the liquid-crystal panel W andlaminating the sheet to the liquid-crystal panel W.

In addition, the polarizing composite film 11 constituting a continuousweb of an optical film laminate 15 used for a continuous web of anoptical film with predefined slit lines 10 may be made of a polarizerincluding a substrate of a PVA based material having at least onesurface laminated with a protection film, preferably of a transparentmaterial, with an adhesive layer 12 provided on the other surface. Acontinuous web of a carrier film 13 is releasably attached to theadhesive layer 12. In the conventional liquid-crystal display elementmanufacturing process using individualized sheets, generally, a sheetcomprising a polarizer having two protection films laminated thereon atthe opposite surfaces to impart stiffness to it is used as thepolarizing composite film 11 as described above. However, in aliquid-crystal display element manufacturing process using thecontinuous web of the optical film with predefined slit lines 10 inaccordance with various embodiments, the normal polarizing sheet x_(α)of the polarizing composite film 11 is separately and continuouslyformed on the carrier film 13 so that the continuous normal polarizingsheet x_(α) is peeled continuously from the carrier film andsequentially laminated to the liquid-crystal panel W at the laminationunit 200 in the lamination station B. Then the normal polarizing sheetx_(α) may come out gradually. It is understood that there is no need topeel the separator on a sheet-by-sheet basis as in the manufacturingprocess using the individualized sheets. When the normal polarizingsheet x_(α) is peeled from the carrier film 13, the leading edge of thenormal polarizing sheet x_(α) is continuously registered with theleading edge of a corresponding one of a plurality of liquid-crystalpanels W being sequentially conveyed on a sheet-by-sheet basis towardthe lamination position, and then, the normal polarizing sheet x_(α) andthe corresponding liquid-crystal panel W are laminated together by beingpressed against each other by a pair of lamination rollers of thelamination unit 200. In this process, there is no risk that theperiphery of the normal polarizing sheet x_(α) is bowed or warped sincethe sheet gradually comes out. Thus, differently from the individualizedsheet, in the polarizing composite film 11 included in the continuousweb of the optical film with predefined slit lines 10 in variousembodiments, the protection film may be laminated to only one of thesurfaces of the polarizer.

3. Manufacturing Method and System for Continuous Web of Optical FilmLaminate with Predefined Slit Lines

The best mode for carrying out the disclosure for continuous web ofoptical film laminate with predefined slit lines for use in a systemsequentially manufacturing liquid-crystal display elements by laminatingeach of a plurality of optically functional film sheets to each of aplurality of liquid-crystal panels, the optically functional film beingformed to have a predefined dimension corresponding to a dimension ofthe liquid-crystal panel having a predefined size, and the manufacturingmethod and system will be described below with reference to the relatedfigures. In the following description, an optical film laminate withpredefined slit lines will be referred to as “optical film withpredefined slit lines” and an optically functional film will be referredto as “polarizing composite film.”

FIGS. 10 and 11 are schematic diagrams showing manufacturing methods andsystems for a continuous web of an optical film with predefined slitlines 10, according to the embodiments shown in FIGS. 10 and 11 of thepresent disclosure. FIGS. 12 to 13 are flowcharts showing respectivemanufacturing processes or process steps in the manufacturing methodsand systems for a continuous web of an optical film with predefined slitlines 10, according to the embodiments shown in FIGS. 10 and 11 of thepresent disclosure.

Description will now be made on the manufacturing method and system forthe continuous web of an optical-film with predefined slit lines,according to the embodiments shown in FIGS. 10 and 11, taking referencesto FIGS. 10 and 12, and FIGS. 11 and 13, respectively.

(Manufacturing Method and System of Continuous Web of Optical Film withPredefined Slit Lines According to an Embodiment)

FIG. 10 is a schematic diagram of the system 500 including the followingmanufacturing line. The system 500 comprises a polarizer manufacturingline 510 for producing a continuous web of a polarizer (hereinafterreferred to as “polarizer” as in the previous description), a protectionfilm manufacturing line 520 for producing a protection film to belaminated on the polarizer, and a polarizing composite filmmanufacturing line 530 for producing a continuous web of a polarizingcomposite film without adhesive layer 11″ consisting of the polarizerand the protection film laminated thereon (hereinafter referred to as“polarizing composite film without adhesive layer 11” to distinguish itfrom the polarizing composite film 11 having an adhesive layer). Themanufacturing line 530 further comprises an inspection station M for thepolarizing composite film without adhesive layer 11″ which inspectssurfaces and inside of the polarizing composite film without adhesivelayer 11″ to detect position of a defect or defects existing in thepolarizing composite film without adhesive layer 11″.

The manufacturing system 500 further comprises a manufacturing line 540for producing a continuous web of an optical film laminate 15 byreleasably laminating the carrier film 13 and the surface-protectionfilm 14 on the inspected polarizing composite film without adhesivelayer 11″. The manufacturing line 540 further comprises a slit-formingstation N that makes slits in the transverse direction of the continuousweb of the optical film laminate 15 each corresponding to thedefect-free region (x_(α)) and the defective region (x_(β)) definedalong the widthwise direction with respect to the predeterminedlongitudinal direction of the polarizing composite film without adhesivelayer 11″ and sequentially forms slit lines 16 on the continuous web ofthe optical film laminate 15, and a slit-position checkup station P thatchecks the position of slit lines 16 formed on the continuous web of theoptical film laminate 15 at the position aligned with the position ofslit-forming station N. The manufacturing system 500 may also comprise,at a final stage, a manufacturing line 550 for taking up themanufactured continuous web of the optical film with slit lines 10 intoa continuous roll.

FIG. 12 is a flowchart showing the manufacturing processes or processsteps in the manufacturing system 500. The manufacturing system 500comprises manufacturing processes or process steps shown in FIG. 12between the manufacturing line 530 for laminating a surface-protectionfilm to one of the surfaces of the polarizer to produce a continuous webof a polarizing composite film without adhesive layer 11″, and themanufacturing line 550 for taking up the manufactured continuous web ofthe optical film with predefined slit lines 10 into a continuous roll ofmanufactured continuous web of optical film laminate with predefinedslit lines 620.

The polarizer manufacturing line 510 has a roll of PVA-based film whichconstitute the substrate of the polarizer and is mounted thereon in arotatable manner, and includes a sub-line for subjecting the PVA-basedfilm being unrolled from the roll by means of a lamination drivemechanism 560 or other drive mechanism (not shown), processes of dyeing,cross-linking, stretching and then drying. The protection filmmanufacturing line 520 has rotatably mounted thereon a continuous rollof a typically transparent TAC-based film constituting a substrate ofthe protection film, and includes a sub-line for subjecting thetransparent TAC-based film being unrolled from the continuous roll bymeans of a lamination drive mechanism 560 or other drive mechanism (notshown), to a saponifying treatment followed by drying. In the case wheretwo protective films are laminated on the opposite surfaces of thepolarizer, the present manufacturing system 500 will include twoprotection film manufacturing lines 520, 520′ (description of theprotection film manufacturing line 520′ is omitted in the drawing).Further, the protective film manufacturing line 520 may additionallyinclude a treatment sub-line for, before a protection film is laminatedto the polarizer, subjecting the surface of the protection film to ahard coat treatment and/or an anti-dazzling or anti-glare treatment.

The polarizing composite film without adhesive layer 11″ manufacturingline 530 includes a sub-line for applying an adhesive consistingprimarily of a polyvinyl alcohol-based resin to an interface between thepolarizer and the protection film, and drying the adhesive to bond themtogether through an adhesive layer having a thickness of only severalμm. The manufacturing line 530 further comprises the lamination drivemechanism 560 including a pair of lamination rollers 561, and in one ofthe pair of lamination rollers 561, a length or distance measurementdevice 570 having an encoder incorporated therein is provided, andincludes a measurement process measuring a fed-out distance of thepolarizing composite film without adhesive layer 11″ fed out from thelamination drive mechanism 560 by means of the distance measurementdevice 570.

The manufacturing line 530 comprises the inspection station M and itincludes an inspection process for detecting defects in the polarizingcomposite film without adhesive layer 11″ by inspecting the surface andinside of the transported continuous web of the polarizing compositefilm without adhesive layer 11″. As described in detail later, at theinspection station M, the control unit 700, connected with theinspection unit 580, executes information processing, wherein thecontrol unit operates the information processing device 710 and thestorage device 720 to determine and store the defect-free region (x_(α))having a predetermined length in a longitudinal direction and thedefective region (x_(β)) including at least one defect and defined as aregion having a predefined length which is different from the length ofthe defect-free region, the length of the defective region being definedacross the position of the defect, the defect-free region (x_(α)) andthe defective region (x_(β)) being defined along the widthwise directionwith respect to the longitudinal direction of the polarizing compositefilm without adhesive layer 11″ based on the position of a defect ordefects existing in and detected through a preliminary inspection, andwhen a continuous web of an optical film laminate 15 is manufactured,executes information processing to produce slit-position information forsequentially forming slit lines 16 in the transverse direction on acontinuous web of an optical film laminate 15, the slit linescorresponding to the stored defect-free region (x_(α)) and defectiveregion (x_(β)) using the slitting unit 600 provided in the slit-formingstation N. The following is an outline of information processing inmanufacturing the continuous web of the optical film with predefinedslit lines 10 wherein the control unit 700 operates to producepolarizing sheets in sequence on the carrier film 13 composing thecontinuous web of the optical film laminate 15 based on slit-positioninformation generated by the information processing.

The control unit 700 functions to operate the information processingdevice 710 and the storage device 720 to process the image data from theimage reading device 581 in association with the feed-length measurementdata based on the delivered length measured by the length or distancemeasurement device 570 as a length from the leading edge of thepolarizing composite film without adhesive layer 11″, so as to produceposition data representing locations or coordinate positions of a defector defects in the polarizing composite film without adhesive layer 11″,and the position data being then stored in the storage device 720. Then,the control unit 700 functions, based on the position data on thedetected locations of a defect or defects, to define defect-free regions(x_(α)) and defective regions (x_(β)) in the polarizing composite film11. Further, the control unit 700 functions to produce a slit positioninformation for sequentially forming the normal polarizing sheet x_(α)and defective polarizing sheet x_(β) being separated from the normalpolarizing sheet in the polarizing composite film 11 having an adhesivelayer, each corresponding to the defect-free region (x_(α)) and thedefective region (x_(β)) in the defined polarizing composite filmwithout adhesive layer 11″, on the carrier film 13 of the continuous webof the optical film laminate 15 to be manufactured in the later process,at the slit-forming station N, using the slitting unit 600. Theslit-position information is provided for indicating positions at whichrespective ones of the slit lines 16 are to be formed in the continuousweb of the optical film laminate and is also stored in the storagedevice 720.

The normal polarizing sheets x_(α) of the polarizing composite film 11having the adhesive layer 12, which has a width corresponding to thedimension of the liquid-crystal panel W, and formed by separating alongtwo slit lines, one on the upstream side and one on the downstream side,in the direction transverse to the longitudinal direction, has apredefined length x_(α) that matches with that of the liquid-crystalpanel W. On the contrary, the defective polarizing sheets x_(β) has alength x_(β) having a predefined length x being defined across a defector defects, more specifically, the upstream one of the two slit lines 16for the normal polarizing sheet x_(α) located just upstream of thedefective polarizing sheet x_(β) in a feed direction can be used as thedownstream one of the two slit lines 16 for the defective polarizingsheet x_(β), so that the defective polarizing sheet x_(β) has a lengthx_(β) that is determined by the downstream slit line 16 of the defectivepolarizing sheet x_(β) and the upstream slit line 16 of the defectivepolarizing sheet x_(β) (this can be used as the slit line correspondingto the downstream slit line 16 of the next normal polarizing sheetx_(α)). Since the length in the feed direction between the downstreamslit line of the defective polarizing sheet x_(β) and the nearestlocation of a defect may not be the same, the length x_(β) of thedefective polarizing sheet varies. Preferably, a calculation algorithmfor producing the slit-position information indicating the positions forforming the slit lines is configured such that the length x_(β) of thedefective polarizing sheet is different from the length x_(α) of thenormal polarizing sheet x_(α), i.e., to have a relation x_(β)≠x_(α), inany case, as described later in detail. The details of informationprocessing are common in the embodiments shown in FIGS. 10 and 11, andit will be described later in connection with reference to FIG. 15.

The manufacturing line 540 for manufacturing a continuous web of anoptical film laminate 15 comprises the following process. Themanufacturing process includes a carrier film lamination process inwhich the carrier film 13 is releasably laminated to the inspectedpolarizing composite film without adhesive layer 11″ by the carrier filmlamination unit 590 and a surface-protection film lamination process inwhich, when necessary, the surface-protection film 14 is releasablylaminated to the surface of the polarizing composite film withoutadhesive layer 11″ opposite to the surface on which the carrier film 13is laminated, by the lamination unit 640.

More specifically, the manufacturing steps are as follows. Referring tothe flow chart of FIG. 12, in Step 1, the lamination drive mechanism 560functions to laminate the protection film to one surface of thepolarizer to thereby produce the polarizing composite film withoutadhesive layer 11″ which is then fed while being produced. In Step 2,the manufactured polarizing composite film without adhesive layer 11″ istransported to an inspection station M and defects existing in thepolarizing composite film without adhesive layer 11″ are detected by theinspection unit 580. In step 3, the continuous roll of the carrier film13 is rotatably mounted on the support rack 591. In step 4, areleasable-film take up drive mechanism 592 and an optical-film take updrive mechanism 630 function to unroll the carrier film 13 from thecontinuous roll with the transferable adhesive layer 12 in exposedstate. In step 5, the carrier film 13 is releasably laminated on thepolarizing composite film without adhesive layer 11″ through theadhesive layer 12 by the carrier-film lamination unit 590, to form thepolarizing composite film 11 having the adhesive layer 12.

Although the descriptions have been made herein with respect to aprocess wherein the step of forming the adhesive layer 12 on thepolarizing composite film without adhesive layer 11″, simultaneouslywith the step of laminating the carrier film 13 on the adhesive layer12, it is to be understood that the adhesive layer 12 may bepreliminarily formed on the polarizing composite film without adhesivelayer 11″. Further, the adhesive surface of the surface-protection film14 may be additionally laminated on the surface of the polarizingcomposite film without adhesive layer 11″ opposite to the surface onewhich the carrier film 13 is laminated by means of the lamination unit640, irrespective of whether the protection film is subjected to thehard coating treatment or the anti-dazzling or anti-glare treatment,before the protection film is laminated to the polarizer. In this case,the manufactured continuous web of the optical film laminate 15 has astructure having the carrier film 13 and the surface-protection film 14laminated on respective ones of the opposite surfaces of the polarizingcomposite film 11.

The manufacturing line 540 includes the slitting station N, and has aprocess comprising the following steps, wherein, in accordance with theinstruction information to sequentially form slit lines 16 in acontinuous web of an optical film laminate 15 after informationprocessing at the inspection station M, the slitting unit 600 providedon the slit-forming station N forms slits at a side opposite to thecarrier film 13 to a depth reaching the surface of the carrier filmadjacent to the adhesive layer of the continuous web of the optical filmlaminate 15 to form slit lines 16 sequentially, so that the normalpolarizing sheet x_(α) and defective polarizing sheet x_(β) beingseparated from the normal polarizing sheet of the polarizing compositefilm 11 having the adhesive layer 12, each corresponding to thedefect-free region (x_(α)) and the defective region (x_(β)) of thepolarizing composite film without adhesive layer 11″ is sequentiallyformed on the carrier film 13.

The manufacturing line 540 further includes a slit-line check station P,and has processes comprising steps, wherein the slitting positioncheckup unit 610 that includes two image-reading devices 611, one onupstream of and one on downstream of the slitting unit 600, checks adeviation between the position of the slit line 16 actually formed andthe slitting position at which the slit line 16 is to be formed (thereference position) on the continuous web of the optical film laminate15, and, corrects the slitting position or the angle of the slittingunit 600 if there is a deviation. Details are described with referenceto FIG. 14.

FIG. 14 is a schematic diagram showing an operation of the slittingposition checkup unit 610 together with the inspection method forchecking a deviation between the position of the slit line 16 actuallyformed in a direction transverse to a feeding direction and a positionat which the slit line is to be formed (position of the reference slitline) on the continuous web of the optical film laminate 15, the slitline is calculated based on the feed-length measurement data by a lengthmeasurement device 570 in connection with the fed-out length of theoptical film laminate 15.

Two image reading devices 611 in the slitting position checkup unit 610are provided, one on upstream of and one downstream of the slitting unit600 as seen in the feed direction of the optical film. A pair of feedrollers 631 included in the take-up drive mechanism 630 is disposed atthe downstream side of the downstream image reading device 611, and aspeed adjustment unit 660 including a dancer roller is disposed at theupstream side of the upstream image reading device 611. By operating theabove units in an inter-related manner, the continuous web of theoptical film laminate 15 is constantly fed under tension even if it istemporarily stopped at the slitting position.

Coincidence of the position of the slit line 16 actually formed in thedirection transverse to the feed direction of the continuous web of theoptical film laminate 15 with the position at which the slit line 16 isto be formed (position of the reference slit line) on the continuous webof the optical film laminate 15, the slit line is calculated based onthe feed-length measurement data by a distance measurement device 570 inconnection with the fed-out length of the optical film laminate 15, canbe affirmed by determining the accurate positions in the travelingdirection (X direction) and the transverse direction (Y direction) ofthe optical film laminate 15.

One way is to carry out measurements, at two locations, one on upstreamof and one on downstream of the slitting position (the position of theslitting unit 600) where the slit line 16 is to be formed in the opticalfilm laminate 15, for the deviation in X and Y directions on theposition where the slit line is actually formed, the position of theedge (the side end) of the optical film laminate 15 and the positionwhere the slit line is to be formed with respect to respective referencelines. For example, the image reading device 611 may be provided with aCCD camera to take images of the position of the actually formed slitlines in the optical film laminate 15 and the position of the edge ofthe optical film laminate 15 and produce picturized images. Thereference lines corresponding to the actually formed slit lines and theposition of the edge of the optical film are preliminarily provided inthe image-taking regions, and those positions can be determined in termsof differences in contrasts in the taken images. Then, a calculation ismade to determine the distance (deviation) between the predeterminedreference lines and the positions of the actually formed slit-line andthe edge of the optical film, and the location and the angular positionof the slitting unit 600 is corrected forwardly or backwardly withrespect to the feed direction of the continuous web of the optical filmlaminate 15, based on the calculated distance (deviation).

More specifically, as shown in FIG. 12, Steps 5 and 9 are performed tofeed the continuous web of the optical film laminate 15 under tension,and in step 9, a slit line 16 is formed in the continuous web of theoptical film laminate 15. Then, a further step is carried out by the twoimage reading device 611 to read the position of the actually formedslit line 16 in the continuous web of the optical film laminate 15, andto determine whether there is any deviation between the position of theread slit line 16 of the optical film laminate and the position wherethe slit line 16 is to be formed based on the slit-position information,and in the case where there is any deviation, Steps 10 and 11 arecarried out, and corrected, for example, in the following manner.

The manner of the inspection for determining the deviation between theposition of the actually formed slit line 16 of the continuous web ofthe optical film laminate 15 and the position where the slit line 16 isto be formed is carried out for example in accordance with the followingprocedures.

(1) Images of the position (X) of the actually formed slit line 16 ofthe continuous web of the optical film laminate 15 and two positions(Y1, Y2) of the edge of the continuous web of the optical film laminate15 are taken by the image reading device 611, and the images arepicturized for measurement of the position of the actually formed slitline 16 (X) of the continuous web of the optical film laminate 15 andthe positions of the edges (Y1, Y2) of the continuous web of the opticalfilm laminate 15 in terms of the differences in contrasts.

(2) There is a slit line reference position in the form of a lineextending in Y direction at a position intermediate a reference lineextending in Y direction at an upstream position as seen in X directionin the imaging area of one of the image reading devices 611 and anotherreference line extending in Y direction at a downstream position as seenin X direction in the imaging area of the other of the image readingdevices 611, and data γ representing the distance between the upstreamand downstream reference lines is preliminarily stored in the storagedevice 720 via the information processing device 710. Furthermore, thereare upstream and downstream reference lines extending in the X directionin respective ones of the image-taking regions of the image readingdevices 611.

(3) A correction value α for correcting the position of the slit line 16to be formed in X direction in accordance with the slit positioninformation, and a correction value δ for angularly correcting theposition of the slit line 16 in Y direction are calculated based on themeasured positions of the actually formed slit line 16 (X) and the edge(Y1, Y2) of the continuous web of the optical film laminate 15 and thereference lines. The correction value α correspond to the measureddeviation α, or the deviation α between the actual slit line 16 position(X) and the downstream side reference line extending in the Y direction.The correction value δ can be calculated according to Equation 1 shownbelow, based on the deviations in Y direction of the edge of thecontinuous web of optical film laminate 15 at two positions, or thedeviations (β1, β2) of the edge of the continuous web of the opticalfilm laminate with respect to respective ones of the upstream anddownstream reference lines extending in the X direction, and thedistance data γ between the two reference lines.

$\begin{matrix}{\delta = {\cos^{- 1}\left\{ \frac{\gamma}{\sqrt{\gamma^{2} + \left( {\beta_{1} - \beta_{2}} \right)^{2}}} \right\}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

(4) The storage device 720 is used to store correction values (α, δ) forapplying an instruction to the slitting unit 600 to perform an angularposition correction by a value δ and a positional correction by value αin the X direction based on the measured and calculated data so as tomake the slit line conform to the reference line of the position wherethe slit line 16 is to be formed extending in the Y direction.

(5) The slitting unit 600 receives instruction from the control unit 700for the next operation of forming a slit line 16 in the continuous webof the optical film laminate 15 to perform a positional correction inthe feed direction and an angular position correction in a crosswisedirection with respect to the feed direction, based on the storedcorrection values (α, δ) so as to conform to the reference line of theposition where the slit line 16 is to be formed in the continuous web ofthe optical film laminate 15.

(6) Thereafter, the slitting unit 600 operates to form a next slit linein the continuous web of the optical film laminate 15.

The manufacturing line 550 includes a take-up drive mechanism 630including a pair of feed rollers 631 that winds a continuous web of anoptical film with predefined slit lines 10 into a continuous roll ofmanufactured continuous web of optical film laminate with predefinedslit lines 620.

In the embodiment shown in FIG. 10, the polarizing composite film 11having the adhesive layer 12 may also be manufactured by directlyapplying a solvent containing an adhesive to the surface of theinspected polarizing composite film without adhesive layer 11″ which isto be laminated to the liquid-crystal panel W, then drying thepolarizing composite film. However, generally, the polarizing compositefilm 11 having the adhesive layer 12 is manufactured as follows. In amanufacturing process of the carrier film 13, one surface of the carrierfilm 13 to be laminated to the surface of the polarizing composite filmwithout adhesive layer 11″ that is to be laminated to the liquid-crystalpanel W is subjected to a releasing treatment, and then a solventcontaining an adhesive is applied to the treated surface and dried toform a carrier film 13 having the adhesive layer 12. In the carrier filmlamination process in the manufacturing line 540, the carrier film 13having the preliminarily formed adhesive layer 12 is laminated to theinspected polarizing composite film without adhesive layer 11″ by thecarrier film lamination unit 590 so that the adhesive layer 12 formed onthe carrier film 13 can be transferred to the inspected polarizingcomposite film without adhesive layer 11″ to produce a polarizing film11 having the adhesive layer 12. It is understood that the manufacturingline 540 may include a surface-protection film lamination process inwhich the surface-protection film 14 is laminated to the surface of theinspected polarizing composite film without adhesive layer 11″ oppositeto the surface on which the carrier film 13 is laminated by thelamination unit 640.

(Manufacturing Method and System of Continuous Web of Optical Film withPredefined Slit Lines According to the Embodiment Shown in FIG. 11)

A feature of the manufacturing system 500′ according to the embodimentshown in FIG. 11 is that a preliminarily manufactured continuous web ofa provisional optical film laminate 15′ is prepared. Thus, themanufacturing system 500′ does not comprise a manufacturing line forpolarizer or a manufacturing line for a surface-protection film. Also,unlike the manufacturing line 530 in the embodiment shown in FIG. 10, itis not necessary to include a process of applying an adhesive agent tothe interface between the polarizer and the protection film, and dryingthe adhesive to bond them together by the pair of lamination rollers 561comprised in the lamination drive mechanism 560. An equivalent line tothe manufacturing line 530 is the manufacturing line 530′ of thecontinuous web of the provisional optical film laminate 15′ as shown inFIG. 11. The line is the same as the step 1 shown in FIG. 13. Themanufacturing line 530′ comprises a film feed drive mechanism 560′ thatincludes a pair of feed rollers 561′ for feeding a continuous roll ofprovisional optical film laminate 510′ mounted on the support rack 525.

FIG. 11 is a schematic diagram showing the manufacturing system 500′that comprises the following manufacturing lines. The units and devicesin the manufacturing system 500′ shown in FIG. 11 corresponding to thoseof the manufacturing system 500 shown in FIG. 10 are given the samenumbers.

FIG. 13 is a flowchart showing manufacturing processes or process stepsin the manufacturing system 500′.

As shown in FIG. 11, the manufacturing line 530′ of the provisionaloptical film laminate 15′ feeds a continuous web of the provisionaloptical film laminate 15′ including a provisional carrier film 13′(schematically shown at the bottom of FIG. 11) to the peeling station L,and includes a process of peeling the polarizing composite film 11having the adhesive layer 12 that comprises the provisional optical filmlaminate 15′ from the provisional carrier film 13′ that also comprisesthe polarizing composite film 11.

The manufacturing line 530′ comprises the film feed drive mechanism 560′including a pair of feed rollers 561′ and a distance measurement device570′ having an encoder incorporated in one of the lamination rollers,and includes a measurement process to measure a fed-out distance of thecontinuous web of the provisional optical film laminate 15′ from thefilm feed drive mechanism 560′. The manufacturing line 530′ furthercomprises an inspection station M and includes an inspection process tofeed the manufactured polarizing composite film 11 having the adhesivelayer 12 to the inspection station M, and inspect defects existing inthe polarizing composite film 11 having the adhesive layer 12. Themanufacturing of the continuous web of the optical film with predefinedslit lines 10 in the embodiment shown in FIG. 11 is commenced by themanufacturing line 530′.

A provisional carrier film 13′ having a transferable adhesive layer isused in the manufacturing process of the preliminarily preparedcontinuous web of the provisional optical film laminate 15′. It isbecause when the provisional carrier film 13′ is peeled from thecontinuous web of the provisional optical film laminate 15′ in themanufacturing system 500′, the adhesive layer of the provisional carrierfilm 13′ is transferred to the polarizing composite film 11 to producethe polarizing composite film 11 having the adhesive layer 12.

The manufacturing system 500′, as shown in FIG. 11, comprises themanufacturing line 530′ for manufacturing the continuous web of thepolarizing composite film 11 having the adhesive layer 12. Themanufacturing line 530′ includes an inspection station M that is similarto the inspection station M included in the manufacturing system 500 inthe embodiment shown in FIG. 10, and the inspection station M inmanufacturing line 530′ is different from the one in the manufacturingsystem 500 in that the inspection target is the polarizing compositefilm 11 having the adhesive layer 12. The manufacturing system 500′further comprises the manufacturing line 540 and the manufacturing line550, as the manufacturing system 500 in the embodiment shown in FIG. 10.Therefore, the manufacturing system 500′ comprises the following unitsand devices that are common in the manufacturing system 500 in theembodiment shown in FIG. 10: an inspection unit 580 that includes animage reading device 581, a carrier film lamination unit 590 thatincludes a support rack 591 to which a continuous roll of the carrierfilm 13 is provided, a slitting position checkup unit 610 at aslit-position checkup station P which includes a slitting unit 600 at aslitting station N and two image reading devices 611 one on upstream ofand one downstream of the slitting unit 600, a take-up drive mechanism630 that includes a pair of feed rollers which winds the manufacturedcontinuous web of the optical film with predefined slit lines 10, and acontrol unit 700 that includes a continuous information processingdevice 710 and a storage device 720, and also a lamination unit 640 of asurface-protection film when necessary. The unit comprised in themanufacturing system 500′ but not in the manufacturing system 500 in theembodiment shown in FIG. 10 is a provisional carrier film take-up drivemechanism 650 that includes the provisional carrier film peeling unit651 provided in the peeling station L.

The manufacturing system 500′ comprises the processes or process stepsas shown in FIG. 13. In step 1, a continuous roll of provisional opticalfilm laminate 510′ of a provisional optical film laminate 15′, as anexample, is mounted on a support rack 525. For the provisional opticalfilm laminate 15′, a polarizing composite film 11 including a polarizerhaving a protection film laminated to one or each of opposite surfacesof the polarizer, and a provisional carrier film 13′ formed with atransferable adhesive layer 12 and laminated to the polarizing compositefilm 11 is used as an example. In step 2, the continuous web of theoptical film laminate 15′ is fed to the manufacturing line 530′ formanufacturing the polarizing composite film 11 having an adhesive layer12 by the film feed drive mechanism 560′ that includes a pair of feedrollers 561′. In steps 3 and 4, the provisional carrier film 13′ ispeeled and removed from the provisional optical film laminate 15′ by theprovisional-carrier-film peeling unit 651 in the provisional carrierfilm take-up drive mechanism 650, and the polarizing composite film 11with the transferred adhesive layer 12 is manufactured. In step 5, theinspection unit 580 inspects surfaces and the inside of the polarizingcomposite film 11 having the exposed adhesive layer 12, and defectexisting in the polarizing composite film 11 is detected in the samemanner as in the embodiment shown in FIG. 10.

The control unit 700, connected with the inspection unit 580, at theinspection station M, executes information processing wherein thecontrol unit operates the information processing device 710 and thestorage device 720 to determine and store the defect-free region (x_(α))having a predetermined length in a longitudinal direction and thedefective region (x_(β)) including at least one defect and defined as aregion having a predefined length which is different from the length ofthe defect-free region, the length of the defective region being definedacross the position of the defect, the defect-free region (x_(α)) andthe defective region (x_(β)) being defined along the widthwise directionwith respect to the longitudinal direction of the polarizing compositefilm 11 having the adhesive layer 12 based on the position of a defector defects existing in and detected through a preliminary inspection,and when a continuous web of an optical film laminate 15 ismanufactured, executes information processing to produce slit-positioninformation for sequentially forming slit lines 16 in the transversedirection on a continuous web of an optical film laminate 15, the slitlines corresponding to the stored defect-free region (x_(α)) anddefective region (x_(β)) using the slitting unit 600 provided in theslit-forming station N. The following is an outline of informationprocessing in manufacturing the continuous web of the optical film withpredefined slit lines 10 wherein the control unit 700 operates toproduce polarizing sheets in sequence on the carrier film 13 composingthe continuous web of the optical film laminate 15 based onslit-position information generated by the information processing.

Specifically, the control unit 700 functions to operate the informationprocessing device 710 and the storage device 720 to process the imagedata from the image reading device 581 in association with thefeed-length measurement data based on the delivered length measured bythe length or distance measurement device 570 as a length from theleading edge of the polarizing composite film 11 having the adhesivelayer 12, so as to produce position data representing locations orcoordinate positions of a defect or defects in the polarizing compositefilm 11 having the adhesive layer, and the position data being thenstored in the storage device 720. Then, the control unit 700 functions,based on the position data on the detected locations of a defect ordefects, to define defect-free regions (x_(α)) and defective regions(xβ) in the polarizing composite film 11 having the adhesive layer 12.The control unit 700 further functions to produce slit positioninformation for sequentially forming normal polarizing sheet x_(α) anddefective polarizing sheet x_(β) being separated from the normalpolarizing sheet in the polarizing composite film 11 having an adhesivelayer, each corresponding to the defect-free region (x_(α)) and thedefective region (x_(β)) in the defined polarizing composite film 11having the adhesive layer 12, on the carrier film 13 of the continuousweb of the optical film laminate 15 to be manufactured in the laterprocess, at the slit-forming station N, using the slitting unit 600. Theslit-position information is provided for indicating positions at whichrespective ones of the slit lines 16 are to be formed in the continuousweb of the optical film laminate and is also stored in the storagedevice 720. In any case, the above information processing is the same asthe one in the manufacturing system 500 in the embodiment shown in FIG.10.

The manufacturing line 540 for manufacturing a continuous web of anoptical film laminate 15 comprises the following process. Themanufacturing process includes a carrier film lamination process inwhich the carrier film 13 is releasably laminated to the inspectedpolarizing composite film 11 having the adhesive layer by the carrierfilm lamination unit 590 and a surface-protection film laminationprocess in which, when necessary, the surface-protection film 14 isreleasably laminated to the surface of the polarizing composite film 11opposite to the surface on which the carrier film 13 is laminated, bythe lamination unit 640. More specifically, the manufacturing steps areas follows. Referring to the flow chart of FIG. 13, in steps 6 to 8, thecarrier film 13 is releasably laminated on the polarizing composite film11 having the adhesive layer 12 by the carrier-film lamination unit 590,wherein the surface of the carrier film 13 to be laminated is subjectedto a releasing treatment, to form the continuous web of the optical filmlaminate 15. The manufactured continuous web of the optical filmlaminate 15 has the same structure as the continuous web of the opticalfilm laminate 15 manufactured in the manufacturing system 500 in theembodiment shown in FIG. 10.

It may be possible to releasably laminate a surface-protection film 14having an adhesive surface on the surface of the polarizing compositefilm 11 opposite to the surface on which the carrier film 13 islaminated by means of a lamination unit 640, before the protection filmis laminated to the polarizer, irrespective of whether the protectionfilm is subjected to a hard coat treatment or an anti-dazzling oranti-glare treatment on one surface. In this case, the resultingcontinuous web of the optical film laminate 15 has a structure where thecarrier film 13 and the surface-protection film 14 are releasablylaminated to respective ones of the opposite surfaces of the polarizingcomposite film 11 having the adhesive layer 12.

The manufacturing line 540, as the manufacturing line in the embodimentshown in FIG. 10, includes the slitting station N, and has a processcomprising the following steps, wherein, in accordance with theinstruction information to sequentially form slit lines 16 in acontinuous web of an optical film laminate 15 after informationprocessing at the inspection station M, the slitting unit 600 providedon the slit-forming station N forms slits at the side opposite to thecarrier film 13 to a depth reaching the surface of the carrier filmadjacent to the adhesive layer of the continuous web of the optical filmlaminate 15 to form slit lines 16 sequentially, so that the normalpolarizing sheet x_(α) and defective polarizing sheet x_(β) beingseparated from the normal polarizing sheet of the polarizing compositefilm 11 having the adhesive layer 12, each corresponding to thedefect-free region (x_(α)) and the defective region (x_(β)) of thepolarizing composite film 11 is sequentially formed on the carrier film13. The descriptions for each size of the normal polarizing sheet x_(α)and the defective polarizing sheet x_(β) in the longitudinal directionof the polarizing composite film 11 having the adhesive layer 12 formedby two slit lines, one on the upstream side and one on the downstreamside in the widthwise direction with respect to the longitudinaldirection and having a predefined length corresponding to the dimensionof the liquid-crystal panel W are omitted here as the descriptions arethe same as those in the embodiment shown in FIG. 10.

The manufacturing line 540 further includes a slit-line check station P,and has processes comprising steps, wherein the slitting positioncheckup unit 610 that includes two image-reading devices 611, one onupstream of and one on downstream of the slitting unit 600, checks adeviation between the position of the slit line 16 actually formed andthe slitting position at which the slit line 16 is to be formed (thereference position) on the continuous web of the optical film laminate15, and, corrects the slitting position or the angle of the slittingunit 600 if there is a deviation.

More specifically, as shown in FIG. 13, steps 8 and 12 are performed tofeed the continuous web of the optical film laminate 15 under tension,and in step 12, a slit line 16 is formed in the continuous web of theoptical film laminate 15. Then, a further step is carried out by thedownstream image reading device 611 to read the position of the actuallyformed slit line 16 in the continuous web of the optical film laminate15, and to determine whether there is any deviation between the positionof the read slit line 16 of the optical film laminate and the positionwhere the slit line 16 is to be formed based on the slit-positioninformation, and in the case where there is any deviation, steps 13 and14 are carried out. The inspection method for checking a deviationbetween the position of the slit line 16 actually formed and a positionat which the slit line 16 is to be formed on the continuous web of theoptical film laminate 15 is omitted here as the description is the sameas the detailed description of the process at the slit-line checkstation P in the embodiment shown in FIG. 10 with reference to FIG. 14.

The manufacturing line 550 is similar to the one in the manufacturingsystem in the embodiment shown in FIG. 10 and it includes a take-updrive mechanism 630 having a pair of feed rollers 631 to wind acontinuous web of an optical film with predefined slit lines 10 into acontinuous roll of manufactured continuous web of optical film laminatewith predefined slit lines 620. The difference between the manufacturingsystem in the embodiment shown in FIG. 10 and that in the embodimentshown in FIG. 11 is understood from the film section diagram shown inthe bottom of FIGS. 10 and 11.

(Formation of Slit Position Information)

At the inspection station M, both in the first and the embodiment shownin FIG. 11, the control unit 700, connected with the inspection unit580, executes information processing, wherein the control unit operatesthe information processing device 710 and the storage device 720 todetermine and store the defect-free region (x_(α)) and the defectiveregion (x_(β)) including at least one defect and defined as a regionhaving a predefined length which is different from the length of thedefect-free region, the length of the defective region being definedacross the position of the defect, the defect-free region (x_(α)) andthe defective region (x_(β)) being defined along the widthwise directionwith respect to the respective longitudinal direction of the polarizingcomposite film without adhesive layer 11″ (in the case of the embodimentshown in FIG. 10) or the polarizing composite film 11 having theadhesive layer 12 (in the case of the embodiment shown in FIG. 11) basedon the position of a defect or defects existing in and detected througha preliminary inspection, and when a continuous web of an optical filmlaminate 15 is manufactured in the later process, executes informationprocessing to produce slit-position information for sequentially formingslit lines 16 in the transverse direction on a continuous web of anoptical film laminate 15, the slit lines corresponding to the storeddefect-free region (x_(α)) and defective region (x_(β)) using theslitting unit 600 provided in the slit-forming station N. The controlunit 700 operates to produce polarizing sheets in sequence on thecarrier film 13 composing the continuous web of the optical filmlaminate 15 based on slit-position information generated by theinformation processing to manufacture the continuous web of the opticalfilm with predefined slit lines 10.

The steps to form slit line position information that determinespositions of defect-free region (x_(α)) and defective region (x_(β))being defined in the transverse direction with respect to thelongitudinal direction is described below with reference to theschematic diagram in FIG. 15 and flowcharts in FIGS. 16 to 18. It isunderstood that these embodiments are only examples.

FIG. 15 is a schematic diagram showing the feed of the polarizingcomposite film without adhesive layer 11″ to which a surface-protectionfilm is laminated on its polarizer or the polarizing composite filmwithout adhesive layer 11″ having the adhesive layer 12 (hereinafter,both are called polarizing composite film 11) transported continuouslyin the right direction by means of the lamination drive mechanism 560 orthe film feed drive mechanism 560′ and the pair of feed rollers 631included in take-up drive mechanism 630, via the feed roller of thecarrier film lamination unit 590 and the speed adjustment device (notshown) that includes a dancer roller.

FIGS. 16 to 18 are flowcharts showing different manners of calculatingthe positions at which respective ones of the slit lines 16 are to beformed in the continuous web of the optical film laminate 15 beingtransported.

In either case, in step 1, the control unit 700 operates to instruct thelamination drive mechanism 560 and the pair of feed rollers included inthe take-up drive mechanism 630 to feed the polarizing composite film11. In step 2, the control unit 700 operates to instruct the informationprocessing device 710 and the storage device 720 to associate the imagedata from the image reading device 581 and the feed-length measurementdata measured from a leading edge of the polarizing composite film 11 bythe distance measurement device 570 and perform information processingon them, so as to produce position data of positions of defects in thepolarizing composite film 11, and store the data in the storage device720. In steps 3 and 4, the control unit 700 defines the polarizingcomposite film 11 into defect-free region (x_(α)) and defective region(x_(β)) based on the position information on the detected locations of adefect or defects. Further, the control unit 700 produces a slitposition information for sequentially forming the normal polarizingsheet (x_(α)) and defective polarizing sheet (x_(β)) being separatedfrom the normal polarizing sheet in the polarizing composite film 11having an adhesive layer, each corresponding to the defect-free region(x_(α)) and the defective region (x_(β)) in the defined polarizingcomposite film without adhesive layer 11″, on the carrier film 13 of thecontinuous web of the optical film laminate 15 to be manufactured in thelater process, at the slit-forming station N, using the slitting unit600. The slit-position information is provided for indicating positionsat which respective ones of the slit lines 16 are to be formed in thecontinuous web of the optical film laminate and is also stored in thestorage device 720.

In step 3, the control unit 700 functions to operate the informationprocessing device 710 to calculate the distance X between location ofthe defect of the polarizing composite film 11 being fed and thereference position, and store the calculated distance X in the storagedevice 720. As shown in FIG. 15, the distance X is a distance forexample between the position of the inspection unit 580 and the positionof the carrier film lamination unit 590 (or the reference position ofthe polarizing composite film 11).

In Step 4, the control unit 700 further functions to operate theinformation processing device 710 to subtract the length (x_(α))corresponding to that of the defect-free region from the distance x toobtain a distance (x−x_(α))=x′, and then store the distance x′ in thestorage device 720. The length x_(α) corresponding to that of thedefective-free region of the polarizing composite film is determined bya system manager based on the size of the liquid-crystal panel andpre-stored in the storage device 720. Then, the control unit 700functions to operate the information processing device 710 to determinewhether the calculated distance x′ is greater or less than the lengthx_(α) corresponding to that of the defect-free region of the polarizingcomposite film 11. Specifically, if the relation x′ (or x″) in FIG.15>x_(α) is established, it is understood that the defect-free regionx_(α) of the polarizing composite film 11 can be ensured, so that thecontrol unit 700 instructs the lamination drive mechanism 560 or thefilm feed drive mechanism 560′ and the pair of feed rollers 631 includedin the take-up drive mechanism 630 to have the polarizing composite film11 delivered under tension by the length x_(α) of the defect-freeregion. The value of the length x_(α) in this instance is theslit-position information for forming a normal polarizing sheet x_(α)corresponding to the defect-free region (x_(α)) in the polarizingcomposite film 11.

To the contrary, if the relation is x′ (or x″)≦x_(α), i.e., x′″ in FIG.15≦x_(α), it is understood that the defect-free region (x_(α)) of thepolarizing composite film 11 cannot be ensured. In this instance, theregion of the polarizing composite film 11 having the length x_(β)provides the defective region (x_(β)), so that the control unit 700functions to operate the information processing device 710 to calculatethe length (x′+x₀)=x_(β) corresponding to the defective region (x_(β))by adding a constant value x₀ to x′ (x′″ in FIG. 15), and to instructthe lamination drive mechanism 560 or the film feed drive mechanism560′, and the pair of feed rollers 631 included in the take-up drivemechanism 630 to have the polarizing composite film delivered undertension by the length x_(β) of the defective region. The value x_(β) inthis instance is the slit-position information for forming a defectivepolarizing sheet x_(β) corresponding to the defective region (x_(β)) ofthe polarizing composite film 11.

The control unit 700 operates to calculate the following (a) and (b) tocreate slit-position information indicative of the positions at whichrespective ones of the slit lines 16 are to be formed in the continuousweb of the optical film laminate 15 to be manufactured in the laterprocess to form normal polarizing sheets xα and defective polarizingsheets x_(β) of a polarizing composite film 11 having the adhesive layer12, and then store the slit-position information in the storage device720:

(a) a distance x_(α) to the position for forming a next slit line, ifx′>x_(α); and

(b) a distance (x′+x₀=x_(β)) to the position for forming a next slitline, if x′≦x_(α).

If the length (x′+x₀=x_(β)) corresponding to that of the defectiveregion (x_(β)) becomes equal to the length x_(α) corresponding to thatof the defect-free region (x_(α)), i.e., if (x′+x₀)=(x_(α)), the controlunit 700 cannot identify or discriminate the defect-free region (x_(α))over the defective region (x_(β)). This means that the region to berecognized as the defective region (x_(β)) may not be recognized as thedefective region, so that, for example, the defect-free region (x_(α))and the defective region (x_(β)) cannot be discriminated from each otherbased on feed-length measurement data on the feed length of thepolarizing composite film 11, and the information created based on thefeed-length measurement data (x′+x₀) inevitably becomes imperfect. It isassumed that such situation occurs when the position of a defect in thepolarizing composite film 11 is infinitely close to the position forforming a next slit line 16 in the polarizing composite film 11, or whena plurality of a series of defects are distributed over a length x_(α)corresponding to that of the defect-free region.

In step 5, if (x′+x₀)=x_(α) becomes equal to x_(α), the control unit 700functions to operate the information processing device 710 to perform acalculation based on at least one of the following methods to createinformation for identifying or discriminating the defect-free region(x_(α)) over the defective region (x_(β)).

In Step 5 illustrated in FIG. 16, even if, as the result of calculationconducted by the information processing device 710, the distance (x′+x₀)to the position for forming a next slit line 16 becomes equal to thelength x_(α) corresponding to that of the defect-free region, the regionin said distance is not essentially the defect-free region (x_(α)). Inorder to make it possible to recognize such a difference,defective-including information x_(γ) or defective polarizing sheetx_(β) identification information x_(γ) is produced and stored in thestorage device 720, wherein for example, a numerical suffix “0” may beassociated with the slit-position information indicative of the positionfor forming a slit line 16 corresponding to the defect-free region(x_(α)), and a numerical suffix “1” with the slit-position informationindicating the position for forming a-slit line 16 corresponding to thedefective region.

In step 5 illustrated in FIG. 17, if, as a result of calculation of theinformation processing device 710, the distance (x′+x₀) to the positionwhere a next-slit-line is to be formed becomes equal to the length x_(α)corresponding to that of the defect-free region (x_(α)), an informationprocessing is conducted so that the distance to the position where anext-slit-line is to be formed satisfies the relation (x′+x₀′), whereinx₀′>x₀, and store the distance (x′+x₀′) in the storage device 720. Thisinformation processing makes it possible by calculating the distance(x′+x₀′) different from x_(α), to allow the region having the length(x′+x₀′) to be identified or discriminated over the defect-free regionx_(α).

Further, in step 5 illustrated in FIG. 18, if, as the result ofcalculation conducted by the information processing device 710, thedistance (x′+x₀) to the position where a next slit line 16 is to beformed becomes equal to the length x_(α) corresponding to that of thedefect-free region (x_(α)), an information processing is carried out toallow the distance to the position where the next slit line 16 is to beformed to become [(x′+x₀)/m], wherein m=2 or more, preferably 2 or 3,and store the distance [(x′+x₀)/m] in the storage device 720. As in thecase of FIG. 17, this information processing is also configured tocalculate the [(x′+x₀)/m] different from x_(α) to allow the regionhaving the length [(x′+x₀)/m] to be identified or discriminated over thedefect-free region (x_(α)).

Summarizing the above, in the process for creating information foridentifying or discriminating the defect-free region (x_(α)) anddefective region (x_(β)), either of the following methods may beadopted:

(1) A method of creating defect-including information as information foridentifying or discriminating a region having a length (x′+x₀)calculated by the information processing device 710 over the defect-freeregion (x_(α));

(2) A method of creating a distance to the position where a next slitline 16 is to be formed which is calculated by the informationprocessing device 710, as a distance (x′+x₀′) (wherein x₀′>x₀) which isdifferent from the length x_(α); and

(3) A method of creating a distance to the position where a next slitline 16 is to be formed which is calculated by the informationprocessing device 710, as a distance [(x′+x₀)/m] (wherein m=2 or more)which is different from the length x_(α).

Particularly, in cases where the method (2) or (3) is employed,(x′+x₀)=(x_(α)) is changed to (x′+x₀′)≠x_(α) or [(x′+x₀)/m]≠x_(α). Thus,the position where a next-slit-line is to be formed position can be usedas information indicating the defective region (x_(β)) identified ordiscriminated over the defect-free region (x_(α)).

In either case, in step 6, the control unit 700 functions to operate theinformation processing device 710 to determine the length between thereference position (the position of the carrier film lamination unit 590in FIG. 15) and the position where a next-slit-line is to be formed,based on the calculation result in steps 4 and 5. Then, in the methods(2) or (3), in step 7, the control unit 700 operates to cause theslitting position checkup unit 610 to store the length to the positionwhere a next slit line 16 is to be formed as determined in step 6, inthe storage device 720. However, in the case of the method (1), thecontrol unit 700 functions to operate the information processing device710 to store the length to the position of forming a next-slit-line inassociation with the defect-including information x_(γ).

In either case, in Step 8, the control unit 700 functions to operate theslitting unit 600 provided on the slit-forming station N to form slitsat the side opposite to the carrier film 13 to a depth reaching asurface of the carrier film adjacent to the adhesive layer to form slitlines 16 sequentially, so that the normal polarizing sheet x_(α) anddefective polarizing sheet x_(β) being separated from the normalpolarizing sheet, of the polarizing composite film 11 having theadhesive layer 12 composing the continuous web of the optical filmlaminate 15, is sequentially formed on the carrier film 13 alsocomposing the continuous web of the optical film laminate 15, when acontinuous web of an optical film laminate 15 manufactured in the laterprocess is carried to the slit forming station N, based on the positionfor forming a next-slit-line stored in Step 7.

In step 9, the slitting position checkup unit 610 provided in theslit-position checkup station P is adapted to perform the checkupprocess to check if there is a deviation between the position of theslit line 16 actually formed and the stored slitting position at whichthe slit line 16 is to be formed. As described earlier, the deviationbetween the slitting position at which the slit line 16 is to be formed(the reference position) on the continuous web of the optical filmlaminate 15 and the position of the slit line 16 actually formed ischecked, and corrects the slitting position or the angle of the slittingunit 600 if there is a deviation, before forming the next slit line 16.

(Details of Defect Inspection Unit)

FIG. 19 shows one embodiment for detecting defects in a polarizingcomposite film having an adhesive layer according to the embodimentshown in FIG. 11 of the present disclosure whereby: a continuous web ofa provisional optical film laminate 15′ is carried to the peelingstation L, and a provisional carrier film 13′ composing the continuousweb of the provisional optical film laminate 15′ is peeled from thelaminate to produce the polarizing composite film having the adhesivelayer 12, wherein the manufactured polarizing composite film 11 havingthe adhesive layer 12 is inspected at the inspection station Mcomprising three inspection units to inspect the position of a defect ordefects. The inspection units are not limited to those shown in thefigure and are also applicable to the inspection unit M according to theembodiment shown in FIG. 10 of the present disclosure. FIG. 19 furthershows a manufacturing system 800 for manufacturing a continuous roll ofa continuous web of an optical film laminate 15 whereby: a carrier film13 is releasably laminated on the polarizing composite film 11 havingthe adhesive layer 12 and when necessary, the surface-protection film isreleasably laminated on the surface of the polarizing composite film 11opposite to the surface on which the carrier film 13 is laminated toform the continuous roll of the optical film laminate 15. Themanufacturing line for manufacturing the continuous web of the opticalfilm laminate 15 is described in detail in the description of themanufacturing systems 500 and 500′ in the first and the embodiment shownin FIG. 11, therefore, the description is omitted here.

The manufacturing system 800 comprises a take-up drive mechanism 820 forwinding the provisional carrier film 13′ in addition to the film feedunit 810 including a feed roller 811 for feeding the provisional opticalfilm laminate 15′. The manufacturing system 800, as for inspectionunits, comprises the first inspection unit 830, the second inspectionunit 840, and the third inspection unit 850, and these inspection unitsare controlled by the control unit 900 that includes an informationprocessing device 910 and a storage device 920. A carrier film feed unit860 including a lamination unit 861 and a surface-protection film feedunit 870 including a lamination unit 871 provided as needed, operate toreleasably laminate the carrier film 13 to the exposed surface of theadhesive layer 12 of the inspected polarizing composite film 11 havingthe adhesive layer 12, and, when necessary, releasably laminate thesurface-protection film to the surface of the polarizing composite filmopposite to the surface on which the carrier film 13 is laminated. Thus,the continuous web of optical film laminate 15 is manufactured.

As shown in FIG. 19, the inspection units are disposed at respectivethree positions in the manufacturing system 800. The first inspectionunit 830 is located between the feed roller 811 of the film feed unit810 and the take-up drive mechanism 820 for winding the provisionalcarrier film 13′, and adapted to inspect the continuous web of theprovisional optical film laminate 15′ to which the provisional carrierfilm 13′ is laminated. The first inspection unit 830 inspects thesurface of the polarizing composite film 11 by means of reflected light.Defects that can be inspected are defects such as uneven surface,scratches and spots on the surface which are detectable by CCD camera,as shown in FIG. 20.

The second inspection unit 840 is a transmission inspection unit that isdesigned such that light irradiated from a light source is projected tothe polarizing composite film 11 having the adhesive layer 12perpendicular thereto, and to have the light being received by anoptical detection unit to detect one or more defects existing in thepolarizing composite film 11 having the adhesive layer 12 in the form ofa shade. Defects that can be inspected are defects such as foreign itemsor bubbles in the film.

The third inspection unit 850 is a defect inspection unit based on acrossed-Nichol condition. Along with the application of such defectinspection unit, the accuracy of the defect inspection of polarizingcomposite films has dramatically improved. Generally, manufacturers tendto use only the polarizing composite film that has passed the defectinspection based on the crossed-Nichol condition for large-sizeliquid-crystal display elements. The inspection method is as follows.First, the target polarizing composite film 11 having the adhesive layer12 and the polarizing filter for it are disposed in such a manner as toallow their absorption axes to be oriented at a right angle. A lightfrom the light source is irradiated on it and examine the transmittedlight. Thus, one or more defects in the polarizing composite film 11having the adhesive layer 12 is detected as one or more bright spots.The third inspection unit 850 is designed such that a light emitted froma light source is projected to the polarizing composite film having theadhesive layer perpendicularly or obliquely thereto and, with apolarization filter being disposed immediately before an opticaldetection unit so as to make an absorption axis thereof being orientedat a right angle with respect to an absorption axis of the polarizingcomposite film 11 having the adhesive layer 12, the light which haspassed through the polarizing composite film 11 having the adhesivelayer 12 is received by the optical detection unit to thereby detect oneor more defects existing in the polarizing composite film 11 having theadhesive layer 12 as one or more bright spots. As shown in FIG. 20, alldefects, except surface unevenness, are detected by the third inspectionunit 850. Although each of the first, the second and the thirdinspection unit uses the polarizing composite film 11 having theadhesive layer 12 as the inspection target, it is needless to say thatthe polarizing composite film without adhesive layer 11″ or otheroptically functional film can be used as the inspection target.

Although the preferred embodiments have been described, it will beunderstood that various changes and modifications will be made by thoseskilled in the art without departing from the spirit and scope of theinvention. Accordingly, the present disclosure is not limited to thespecific embodiments disclosed as the best mode for carrying out thedisclosure, but intended to cover all embodiments included within thescope thereof.

What is claimed is:
 1. A method of producing a continuous web of anoptical film laminate adapted for use in a system for sequentiallymanufacturing liquid-crystal display elements by laminating opticallyfunctional film sheets formed to respective ones of liquid-crystalpanels, the optically functional film sheets being formed to have apredefined dimension corresponding to a dimension of the liquid-crystalpanels of a predefined size, the method comprising steps of: laminatinga continuous web of a protection film on at least one of oppositesurfaces of a continuous web of a polarizer film to form an opticallyfunctional film having a longitudinal direction; inspecting surfaces andinside of the optically functional film to detect a position of a defectexisting in the optically functional film; releasably laminating acontinuous web of a carrier film on the continuous web of the opticallyfunctional film by an adhesive layer to form a continuous web of theoptical film laminate, wherein the optically functional film includes atleast one defect-free region and at least one defective region, the atleast one defect-free and at least one defective region being definedalong the longitudinal direction of the optically functional film inaccordance with the position of the detected defect, said defect-freeregion having a predefined length corresponding to said dimension of theliquid-crystal panels, said defective region including at least onedefect and defined as a region having a predefined length which isdifferent from the length of said defect-free region, the length of thedefective region being defined across said position of the defect; andsequentially forming slit lines in a transverse direction of saidoptical film laminate at a side opposite to said carrier film to a depthreaching a surface of said carrier film adjacent to said adhesive layerto form, on the carrier film, at least one defect-free, normal opticallyfunctional film sheet having no defect and at least one defectiveoptically functional film sheet having at least one defect, andseparated from the normal sheet, to thereby form a continuous web of theoptical film laminate with slit lines including optically functionalfilm sheets.
 2. The method as defined in claim 1, wherein the methodfurther comprises a step of winding the produced continuous web of theoptical film laminate with slit lines into a roll to form a continuousroll of the optical film laminate with slit lines.
 3. The method asdefined in claim 1, wherein the method further comprises a step offorming a continuous web of optical film laminate that has a widthcorresponding to a width of liquid-crystal panel, and a step ofreleasably laminating a continuous web of surface-protection film on thesurface of the continuous web of the optically functional film oppositeto the surface on which the adhesive layer is laminated.
 4. The methodas defined in claim 1, wherein the step of inspecting surfaces andinside of the optically functional film to detect the position of adefect existing in the optically functional film comprises at least oneof steps of: inspecting a surface of the optically functional film bymeans of reflected light, inspecting inside of the optically functionalfilm by transmitting light irradiated from a light source through theoptically functional film to detect one or more defects existing in theoptically functional film as one or more shades, or detecting one ormore defects as one or more bright spots by cross-Nichol transmissioninspection designed such that the light irradiated from a light sourceis projected to the optically functional film and a polarization filter,and the light which has transmitted through the optically functionalfilm and the polarization filter is examined, with absorption axes ofthe optically functional film and polarization filter being oriented ata right angle.
 5. A method of producing a continuous web of an opticalfilm laminate adapted for use in a system for sequentially manufacturingliquid-crystal display elements by laminating optically functional filmsheets to respective ones of liquid-crystal panels, the opticallyfunctional film sheets being formed to have a predefined dimensioncorresponding to a dimension of a plurality of liquid-crystal panelshaving a predefined size, the method comprising steps of: providing aprovisional optical film laminate at least including a continuous web ofan optically functional film and a continuous web of a provisionalcarrier film, the continuous web of the optically functional filmincluding a laminated web comprising a continuous web of a polarizer, aprotection film laminated on at least one of opposite surfaces of thecontinuous web of polarizer and an adhesive layer provided on one ofopposite surfaces of the laminated web, the continuous web of theprovisional carrier film being releasably laminated on the adhesivelayer; peeling the provisional carrier film from the provisional opticalfilm laminate while feeding the provisional optical film laminate, toexpose the adhesive layer of the optically functional film; inspectingsurfaces and inside of the optically functional film with the adhesivelayer in the exposed state to detect a position of a defect existing inthe optically functional film; releasably laminating a continuous web ofa carrier film on the continuous web of the optically functional film bythe adhesive layer to form a continuous web of the optical filmlaminate, wherein the optically functional film including at least onedefect-free region having no defect and at least one defective region,the defect-free and defective regions being defined along longitudinaldirection in accordance with the position of the detected defect, saiddefect-free region having a predefined length corresponding to saiddimension of said liquid-crystal panels, said defective region having apredefined length which is different from the length of the defect-freeregion, the length of the defective region being defined across thedefect; and sequentially forming slit lines in a transverse direction ofsaid optical film laminate at a side opposite to said carrier film to adepth reaching a surface of said carrier film adjacent to said adhesivelayer to form, on the carrier film, at least one defect-free, normaloptically functional film sheet having no defect and at least onedefective optically functional film sheet having at least one defect, tothereby form a continuous web of the optical film laminate with slitlines including optically functional film sheets.
 6. The method asdefined in claim 5, wherein the method further comprises a step ofwinding the produced continuous web of the optical film laminate withslit lines into a roll to form a continuous roll of the optical filmlaminate with slit lines.
 7. The method as defined in claim 5, whereinthe provisional carrier film has a transferable adhesive layer formedby, after subjecting one of opposite surfaces of the provisional carrierfilm to a releasing treatment, applying a solvent containing an adhesiveto the treated surface and drying the solvent.
 8. The method as definedin claim 5, wherein the surface of a final carrier film which islaminated to the exposed adhesive layer of the optically functional filmis subjected to a releasing treatment.
 9. The method as defined in claim5, wherein the step of forming a continuous web of the optical filmlaminate forms a web of the optical film laminate having a widthcorresponding to the width of the liquid-crystal panel, wherein themethod further includes a step of releasably laminating a continuous webof surface-protection film on the surface of the continuous web of theoptically functional film opposite to the surface on which the adhesivelayer is laminated.
 10. The method as defined in claim 5, wherein thestep of inspecting surfaces and inside of the optically functional filmwith the adhesive layer in the exposed state to detect the position of adefect existing in the optically functional film comprises at least oneof the steps of: inspecting the surface of the optically functional filmby means of reflected light, inspecting the inside of the opticallyfunctional film by transmitting light irradiated from a light sourcethrough the optically functional film to detect one or more defectsexisting in the optically functional film as one or more shades, ordetecting one or more defects as one or more bright spots bycross-Nichol transmission inspection designed such that the lightirradiated from a light source is projected to the optically functionalfilm and a polarization filter, and the light which has transmittedthrough the optically functional film and the polarization filter isexamined, with absorption axes of the optically functional film andpolarization filter being oriented at a right angle.
 11. A method ofproducing a continuous web of an optical film laminate adapted for usein a system for sequentially manufacturing liquid-crystal displayelements by laminating optically functional film sheets to respectiveones of liquid-crystal panels, the optically functional film sheetsbeing formed to have a predefined dimension corresponding to a dimensionof a plurality of liquid-crystal panels having a predefined size, themethod comprising steps of: providing a provisional optical filmlaminate at least including a continuous web of an optically functionalfilm and a continuous web of a provisional carrier film, the continuousweb of the optically functional film including a laminated webcomprising a continuous web of a polarizer, a protection film laminatedon at least one of opposite surfaces of the continuous web of polarizerand an adhesive layer provided on one of opposite surfaces of thelaminated web, the continuous web of the provisional carrier film beingreleasably laminated on the adhesive layer; peeling the provisionalcarrier film from the provisional optical film laminate while feedingthe provisional optical film laminate, to expose the adhesive layer ofthe optically functional film; inspecting surfaces and inside of theoptically functional film with the adhesive layer in the exposed stateto detect a position of a defect existing in the optically functionalfilm; releasably laminating a continuous web of a carrier film on thecontinuous web of the optically functional film by the adhesive layer toform a continuous web of the optical film laminate, wherein theoptically functional film including at least one defect-free regionhaving no defect and at least one defective region, the defect-free anddefective regions being defined along longitudinal direction inaccordance with the position of the detected defect, said defect-freeregion having a predefined length corresponding to said dimension ofsaid liquid-crystal panels, said defective region having a predefinedlength which is different from the length of the defect-free region, thelength of the defective region being defined across the defect; andsequentially forming slit lines in a transverse direction of saidoptical film laminate at a side opposite to said carrier film to a depthreaching a surface of said carrier film adjacent to said adhesive layerto form, on the carrier film, at least one defect-free, normal opticallyfunctional film sheet having no defect and at least one defectiveoptically functional film sheet having at least one defect, to therebyform a continuous web of the optical film laminate with slit linesincluding optically functional film sheets, wherein the surface of afinal carrier film which is laminated to the exposed adhesive layer ofthe optically functional film is subjected to a releasing treatment. 12.The method as defined in claim 11, wherein the method further comprisesa step of winding the produced continuous web of the optical filmlaminate with slit lines into a roll to form a continuous roll of theoptical film laminate with slit lines.
 13. The method as defined inclaim 11, wherein the provisional carrier film has a transferableadhesive layer formed by, after subjecting one of opposite surfaces ofthe provisional carrier film to a releasing treatment, applying asolvent containing an adhesive to the treated surface and drying thesolvent.
 14. The method as defined in claim 11, wherein the step offorming a continuous web of the optical film laminate forms a web of theoptical film laminate having a width corresponding to the width of theliquid-crystal panel, wherein the method further includes a step ofreleasably laminating a continuous web of surface-protection film on thesurface of the continuous web of the optically functional film oppositeto the surface on which the adhesive layer is laminated.
 15. The methodas defined in claim 11, wherein the step of inspecting surfaces andinside of the optically functional film with the adhesive layer in theexposed state to detect the position of a defect existing in theoptically functional film comprises at least one of the steps of:inspecting the surface of the optically functional film by means ofreflected light, inspecting the inside of the optically functional filmby transmitting light irradiated from a light source through theoptically functional film to detect one or more defects existing in theoptically functional film as one or more shades, or detecting one ormore defects as one or more bright spots by cross-Nichol transmissioninspection designed such that the light irradiated from a light sourceis projected to the optically functional film and a polarization filter,and the light which has transmitted through the optically functionalfilm and the polarization filter is examined, with absorption axes ofthe optically functional film and polarization filter being oriented ata right angle.